DAP4 Data Request Form ATL03_20181228015957_13810110_003_01.h5

dataset: ATL03_20181228015957_13810110_003_01.h5
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Global Attributes
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    • Conventions: CF-1.6 (Type is String)
    • contributor_name: Thomas E Neumann (thomas.neumann@nasa.gov), Thorsten Markus (thorsten.markus@nasa.gov), Suneel Bhardwaj (suneel.bhardwaj@nasa.gov) David W Hancock III (david.w.hancock@nasa.gov) (Type is String)
    • contributor_role: Instrument Engineer, Investigator, Principle Investigator, Data Producer, Data Producer (Type is String)
    • date_type: UTC (Type is String)
    • description: This data set (ATL03) contains height above the WGS 84 ellipsoid (ITRF2014 reference frame), latitude, longitude, and time for all photons downlinked by the Advanced Topographic Laser Altimeter System (ATLAS) instrument on board the Ice, Cloud and land Elevation Satellite-2 (ICESat-2). (Type is String)
    • featureType: trajectory (Type is String)
    • geospatial_lat_units: degrees_north (Type is String)
    • geospatial_lon_units: degrees_east (Type is String)
    • granule_type: ATL03 (Type is String)
    • identifier_product_doi_authority: http://dx.doi.org (Type is String)
    • level: L2 (Type is String)
    • license: Data may not be reproduced or distributed without including the citation for this product included in this metadata. Data may not be distributed in an altered form without the written permission of the ICESat-2 Science Project Office at NASA/GSFC. (Type is String)
    • naming_authority: http://dx.doi.org (Type is String)
    • short_name: ATL03 (Type is String)
    • spatial_coverage_type: Horizontal (Type is String)
    • standard_name_vocabulary: CF-1.6 (Type is String)
    • time_type: CCSDS UTC-A (Type is String)
    • title: SET_BY_META (Type is String)
    • date_created: 2020-03-21T12:54:34.000000Z (Type is String)
    • hdfversion: HDF5 1.10.3 (Type is String)
    • history: 2020-03-21T12:54:34.000000Z;5a847446-832e-3206-8ca9-8a632e4d761b;Created by PGE atlas_l2a_alt Version 3.3 (Type is String)
    • identifier_file_uuid: 5a847446-832e-3206-8ca9-8a632e4d761b (Type is String)
    • identifier_product_format_version: 3.3 (Type is String)
    • time_coverage_duration: 461. (Type is Float64)
    • time_coverage_end: 2018-12-28T02:07:38.000000Z (Type is String)
    • time_coverage_start: 2018-12-28T01:59:57.000000Z (Type is String)
    • geospatial_lat_min: -79.002441705550709 (Type is Float64)
    • geospatial_lon_min: -42.33993820187478 (Type is Float64)
    • geospatial_lat_max: -50.209962155122966 (Type is Float64)
    • geospatial_lon_max: -32.276188773376937 (Type is Float64)
    • publisher_name: NSIDC DAAC > NASA National Snow and Ice Data Center Distributed Active Archive Center (Type is String)
    • publisher_email: nsidc@nsidc.org (Type is String)
    • publisher_url: http://nsidc.org/daac/ (Type is String)
    • identifier_product_type: ATL03 (Type is String)
    • identifier_product_doi: doi:10.5067/ATLAS/ATL03.003 (Type is String)
    • institution: National Aeronautics and Space Administration (NASA) (Type is String)
    • creator_name: GSFC I-SIPS > ICESat-2 Science Investigator-led Processing System (Type is String)
    • summary: The purpose of ATL03 is to provide along-track photon data for all 6 ATLAS beams and associated statistics. (Type is String)
    • keywords: EARTH SCIENCE > CRYOSPHERE > SEA ICE > NONE > NONE > NONE > NONE (Type is String)
    • keywords_vocabulary: NASA/GCMD Science Keywords (Type is String)
    • citation: Cite these data in publications as follows: The data used in this study were produced by the ICESat-2 Science Project Office at NASA/GSFC. The data archive site is the NASA National Snow and Ice Data Center Distributed Active Archive Center. (Type is String)
    • processing_level: 2A (Type is String)
    • references: http://nsidc.org/data/icesat2/data.html (Type is String)
    • project: ICESat-2 > Ice, Cloud, and land Elevation Satellite-2 (Type is String)
    • instrument: ATLAS > Advanced Topographic Laser Altimeter System (Type is String)
    • platform: ICESat-2 > Ice, Cloud, and land Elevation Satellite-2 (Type is String)
    • source: Spacecraft (Type is String)
Global Dimensions
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      [ /ds_surf_type = 0..4 ]
      [ /ds_xyz = 0..2 ]
Variables
ds_surf_type[ /ds_surf_type= 0..4] (Type is Int32)
  • attributes
    • contentType: auxiliaryInformation (Type is String)
    • units: 1 (Type is String)
    • description: Dimension scale indexing the surface type array. Index=1 corresponds to Land; index = 2 corresponds to Ocean; Index = 3 corresponds to SeaIce; Index=4 corresponds to LandIce; Index=5 corresponds to InlandWater (Type is String)
    • flag_meanings: land ocean seaice landice inland_water (Type is String)
    • flag_values: 1, 2, 3, 4, 5 (Type is Int32)
    • long_name: Surface Type Dimension Scale (Type is String)
    • valid_max: 5 (Type is Int32)
    • valid_min: 1 (Type is Int32)
ds_xyz[ /ds_xyz= 0..2] (Type is Int32)
  • attributes
    • contentType: auxiliaryInformation (Type is String)
    • flag_meanings: x y z (Type is String)
    • description: Dimension scale indexing the XYZ components of velocity_sc. Index=1 corresponds to X; index = 2 corresponds to Y; Index = 3 corresponds to Z; (Type is String)
    • flag_values: 1, 2, 3 (Type is Int32)
    • long_name: XYZ Dimension Scale (Type is String)
    • units: 1 (Type is String)
    • valid_max: 3 (Type is Int32)
    • valid_min: 1 (Type is Int32)
orbit_info(Type is Group)
  • attributes
    • Description: Contains data that are common among all beams for the granule. These parameters are constants for a given granule. (Type is String)
    • data_rate: These parameters are constant for a given granule. (Type is String)
Dimensions: [ /orbit_info/crossing_time = 0..0 ] [ /orbit_info/sc_orient_time = 0..0 ]
  • crossing_time[ /orbit_info/crossing_time= 0..0] (Type is Float64)
    • attributes
      • contentType: referenceInformation (Type is String)
      • description: The time, in seconds since the ATLAS SDP GPS Epoch, at which the ascending node crosses the equator. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
      • long_name: Ascending Node Crossing Time (Type is String)
      • source: POD/PPD (Type is String)
      • standard_name: time (Type is String)
      • units: seconds since 2018-01-01 (Type is String)
  • sc_orient_time[ /orbit_info/sc_orient_time= 0..0] (Type is Float64)
    • attributes
      • contentType: referenceInformation (Type is String)
      • description: The time of the last spacecraft orientation change between forward, backward and transitional flight modes, expressed in seconds since the ATLAS SDP GPS Epoch. ICESat-2 is considered to be flying forward when the weak beams are leading the strong beams; and backward when the strong beams are leading the weak beams. ICESat-2 is considered to be in transition while it is maneuvering between the two orientations. Science quality is potentially degraded while in transition mode. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
      • long_name: Time of Last Spacecraft Orientation Change (Type is String)
      • source: POD/PPD (Type is String)
      • standard_name: time (Type is String)
      • units: seconds since 2018-01-01 (Type is String)
  • orbit_number[ /orbit_info/crossing_time= 0..0] (Type is UInt16)
    • attributes
      • contentType: referenceInformation (Type is String)
      • coordinates: crossing_time (Type is String)
      • description: Unique identifying number for each planned ICESat-2 orbit. (Type is String)
      • long_name: Orbit Number (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
      • valid_max: 65000 (Type is UInt16)
      • valid_min: 1 (Type is UInt16)
  • rgt[ /orbit_info/crossing_time= 0..0] (Type is Int16)
    • attributes
      • contentType: referenceInformation (Type is String)
      • coordinates: crossing_time (Type is String)
      • description: The reference ground track (RGT) is the track on the earth at which a specified unit vector within the observatory is pointed. Under nominal operating conditions, there will be no data collected along the RGT, as the RGT is spanned by GT2L and GT2R. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. (Type is String)
      • long_name: Reference Ground track (Type is String)
      • source: POD/PPD (Type is String)
      • units: counts (Type is String)
      • valid_max: 1387 (Type is Int16)
      • valid_min: 1 (Type is Int16)
  • sc_orient[ /orbit_info/sc_orient_time= 0..0] (Type is Int8)
    • attributes
      • contentType: referenceInformation (Type is String)
      • coordinates: sc_orient_time (Type is String)
      • description: This parameter tracks the spacecraft orientation between forward, backward and transitional flight modes. ICESat-2 is considered to be flying forward when the weak beams are leading the strong beams; and backward when the strong beams are leading the weak beams. ICESat-2 is considered to be in transition while it is maneuvering between the two orientations. Science quality is potentially degraded while in transition mode. (Type is String)
      • flag_meanings: backward forward transition (Type is String)
      • flag_values: 0, 1, 2 (Type is Int8)
      • long_name: Spacecraft Orientation (Type is String)
      • source: POD/PPD (Type is String)
      • units: 1 (Type is String)
      • valid_max: 2 (Type is Int8)
      • valid_min: 0 (Type is Int8)
  • cycle_number[ /orbit_info/crossing_time= 0..0] (Type is Int8)
    • attributes
      • contentType: referenceInformation (Type is String)
      • coordinates: crossing_time (Type is String)
      • description: Tracks the number of 91-day cycles in the mission, beginning with 01. A unique orbit number can be determined by subtracting 1 from the cycle_number, multiplying by 1387 and adding the rgt value. (Type is String)
      • long_name: Cycle Number (Type is String)
      • source: POD/PPD (Type is String)
      • units: counts (Type is String)
      • valid_max: 50 (Type is Int8)
      • valid_min: 0 (Type is Int8)
  • lan[ /orbit_info/crossing_time= 0..0] (Type is Float64)
    • attributes
      • contentType: referenceInformation (Type is String)
      • coordinates: crossing_time (Type is String)
      • description: Longitude at the ascending node crossing. (Type is String)
      • long_name: Ascending Node Longitude (Type is String)
      • source: POD/PPD (Type is String)
      • units: degrees_east (Type is String)
      • valid_max: 180. (Type is Float64)
      • valid_min: -180. (Type is Float64)
METADATA(Type is Group)
  • attributes
    • Description: ISO19115 Structured Metadata Represented within HDF5 (Type is String)
    • iso_19139_dataset_xml: <?xml version="1.0"?> <gmd:DS_Series xsi:schemaLocation="http://www.isotc211.org/2005/gmi http://cdn.earthdata.nasa.gov/iso/schema/1.0/ISO19115-2_EOS.xsd" xmlns:eos="http://earthdata.nasa.gov/schema/eos" xmlns:gco="http://www.isotc211.org/2005/gco" xmlns:gmd="http://www.isotc211.org/2005/gmd" xmlns:gmi="http://www.isotc211.org/2005/gmi" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:gmx="http://www.isotc211.org/2005/gmx" xmlns:gsr="http://www.isotc211.org/2005/gsr" xmlns:gss="http://www.isotc211.org/2005/gss" xmlns:gts="http://www.isotc211.org/2005/gts" xmlns:srv="http://www.isotc211.org/2005/srv" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <gmd:composedOf> <gmd:DS_DataSet> <gmd:has> <gmi:MI_Metadata> <gmd:fileIdentifier> <gmx:FileName>ATL03_20181228015957_13810110_003_01.h5</gmx:FileName> </gmd:fileIdentifier> <gmd:contact> <gmd:CI_ResponsibleParty> <gmd:organisationName> <gco:CharacterString>NSIDC DAAC &gt; National Snow and Ice Data Center DAAC</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo> <gmd:CI_Contact> <gmd:address> <gmd:CI_Address> <gmd:electronicMailAddress> <gco:CharacterString>nsidc@nsidc.org</gco:CharacterString> </gmd:electronicMailAddress> </gmd:CI_Address> </gmd:address> <gmd:onlineResource> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://nsidc.org/daac/</gmd:URL> </gmd:linkage> </gmd:CI_OnlineResource> </gmd:onlineResource> </gmd:CI_Contact> </gmd:contactInfo> <gmd:role> <gmd:CI_RoleCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:contact> <gmd:dateStamp> <gco:DateTime>2020-03-21T12:54:34.000000Z</gco:DateTime> </gmd:dateStamp> <gmd:metadataStandardName> <gco:CharacterString>ISO 19115-2 Geographic information - Metadata - Part 2: Extensions for imagery and gridded data</gco:CharacterString> </gmd:metadataStandardName> <gmd:metadataStandardVersion> <gco:CharacterString>ISO 19115-2:2009-02-15</gco:CharacterString> </gmd:metadataStandardVersion> <gmd:identificationInfo> <gmd:MD_DataIdentification> <gmd:citation> <gmd:CI_Citation> <gmd:title> <gmx:FileName>ATL03_20181228015957_13810110_003_01.h5</gmx:FileName> </gmd:title> <gmd:date> <gmd:CI_Date> <gmd:date> <gco:DateTime>2020-03-21T12:54:34.000000Z</gco:DateTime> </gmd:date> <gmd:dateType> <gmd:CI_DateTypeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode> </gmd:dateType> </gmd:CI_Date> </gmd:date> <gmd:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>ATL03</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>The ECS Short Name</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> <gmd:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>003</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>The ECS Version ID</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> <gmd:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>ATL03_20181228015957_13810110_003_01.h5</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>ProducerGranuleId</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> </gmd:CI_Citation> </gmd:citation> <gmd:abstract> <gco:CharacterString>The ICESat-2 ATL03 standard data product contains precise latitude, longitude and height above ellipsoid for all received photons. Geophysical corrections are applied to the photon height values and each photon is classified as signal vs. background. Includes segmented data at a 20-meter along-track length. Geophysical corrections, atmosphere corrections and the surface types (land ice, sea ice, ocean, land, inland water) are provided for each 20-meter segment.</gco:CharacterString> </gmd:abstract> <gmd:status> <gmd:MD_ProgressCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ProgressCode" codeListValue="onGoing">onGoing</gmd:MD_ProgressCode> </gmd:status> <gmd:aggregationInfo> <gmd:MD_AggregateInformation> <gmd:aggregateDataSetName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>ATL03</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:edition> <gco:CharacterString>003</gco:CharacterString> </gmd:edition> </gmd:CI_Citation> </gmd:aggregateDataSetName> <gmd:associationType> <gmd:DS_AssociationTypeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#DS_AssociationTypeCode" codeListValue="largerWorkCitation">largerWorkCitation</gmd:DS_AssociationTypeCode> </gmd:associationType> </gmd:MD_AggregateInformation> </gmd:aggregationInfo> <gmd:language> <gco:CharacterString>eng</gco:CharacterString> </gmd:language> <gmd:topicCategory> <gmd:MD_TopicCategoryCode>geoscientificInformation</gmd:MD_TopicCategoryCode> </gmd:topicCategory> <gmd:extent> <gmd:EX_Extent id="boundingExtent"> <gmd:geographicElement> <gmd:EX_GeographicDescription id="Orbit"> <gmd:geographicIdentifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>AscendingCrossing: 165.20695928840985 StartLatitude: -50.000000000000000 StartDirection:D EndLatitude: -79.000000000000000 EndDirection: D</gco:CharacterString> </gmd:code> <gmd:codeSpace> <gco:CharacterString>gov.nasa.esdis.umm.orbitparameters</gco:CharacterString> </gmd:codeSpace> <gmd:description> <gco:CharacterString>OrbitParameters</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:geographicIdentifier> </gmd:EX_GeographicDescription> </gmd:geographicElement> <gmd:geographicElement> <gmd:EX_GeographicDescription id="OrbitCalculatedSpatialDomains0"> <gmd:geographicIdentifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>OrbitNumber: 1582 EquatorCrossingLongitude: 165.20695928840985 EquatorCrossingDateTime: 2018-12-28T00:59:49.304986Z</gco:CharacterString> </gmd:code> <gmd:codeSpace> <gco:CharacterString>gov.nasa.esdis.umm.orbitcalculatedspatialdomains</gco:CharacterString> </gmd:codeSpace> <gmd:description> <gco:CharacterString>OrbitCalculatedSpatialDomains</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:geographicIdentifier> </gmd:EX_GeographicDescription> </gmd:geographicElement> <gmd:temporalElement> <gmd:EX_TemporalExtent> <gmd:extent> <gml:TimePeriod gml:id="TIME_PERIOD_ID"> <gml:beginPosition>2018-12-28T02:00:01.217090Z</gml:beginPosition> <gml:endPosition>2018-12-28T02:07:38.713000Z</gml:endPosition> </gml:TimePeriod> </gmd:extent> </gmd:EX_TemporalExtent> </gmd:temporalElement> </gmd:EX_Extent> </gmd:extent> </gmd:MD_DataIdentification> </gmd:identificationInfo> <gmd:dataQualityInfo> <gmd:DQ_DataQuality> <gmd:scope> <gmd:DQ_Scope> <gmd:level> <gmd:MD_ScopeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode" codeListValue="dataset">dataset</gmd:MD_ScopeCode> </gmd:level> </gmd:DQ_Scope> </gmd:scope> <gmd:lineage> <gmd:LI_Lineage> <gmd:processStep> <gmi:LE_ProcessStep> <gmd:description> <gco:CharacterString>2020-03-21T12:54:34.000000Z;5a847446-832e-3206-8ca9-8a632e4d761b;Created by PGE atlas_l2a_alt Version 3.3</gco:CharacterString> </gmd:description> <gmd:dateTime> <gco:DateTime>2020-03-21T12:54:34.000000Z</gco:DateTime> </gmd:dateTime> </gmi:LE_ProcessStep> </gmd:processStep> </gmd:LI_Lineage> </gmd:lineage> </gmd:DQ_DataQuality> </gmd:dataQualityInfo> </gmi:MI_Metadata> </gmd:has> </gmd:DS_DataSet> </gmd:composedOf> <gmd:seriesMetadata gco:nilReason="missing"/> </gmd:DS_Series> (Type is String)
    • iso_19139_series_xml: <?xml version="1.0" encoding="UTF-8"?> <gmd:DS_Series xmlns:eos="http://earthdata.nasa.gov/schema/eos" xmlns:gco="http://www.isotc211.org/2005/gco" xmlns:gmd="http://www.isotc211.org/2005/gmd" xmlns:gmi="http://www.isotc211.org/2005/gmi" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:gmx="http://www.isotc211.org/2005/gmx" xmlns:gsr="http://www.isotc211.org/2005/gsr" xmlns:gss="http://www.isotc211.org/2005/gss" xmlns:gts="http://www.isotc211.org/2005/gts" xmlns:srv="http://www.isotc211.org/2005/srv" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.isotc211.org/2005/gmi http://cdn.earthdata.nasa.gov/iso/schema/1.0/ISO19115-2_EOS.xsd"> <gmd:composedOf gco:nilReason="inapplicable"/> <gmd:seriesMetadata> <gmi:MI_Metadata> <gmd:fileIdentifier> <gco:CharacterString>ATL03.003</gco:CharacterString> </gmd:fileIdentifier> <gmd:language> <gco:CharacterString>eng</gco:CharacterString> </gmd:language> <gmd:characterSet> <gmd:MD_CharacterSetCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_CharacterSetCode" codeListValue="utf8">utf8</gmd:MD_CharacterSetCode> </gmd:characterSet> <gmd:hierarchyLevel> <gmd:MD_ScopeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_ScopeCode" codeListValue="series">series</gmd:MD_ScopeCode> </gmd:hierarchyLevel> <gmd:contact> <gmd:CI_ResponsibleParty> <gmd:organisationName> <gco:CharacterString>NSIDC DAAC &gt; NASA National Snow and Ice Data Center Distributed Active Archive Center</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo> <gmd:CI_Contact id="NSIDC_DAAC_CONTACT_ID"> <gmd:phone> <gmd:CI_Telephone> <gmd:voice> <gco:CharacterString>303-492-6199</gco:CharacterString> </gmd:voice> <gmd:facsimile> <gco:CharacterString>303-492-2468</gco:CharacterString> </gmd:facsimile> </gmd:CI_Telephone> </gmd:phone> <gmd:address> <gmd:CI_Address> <gmd:deliveryPoint> <gco:CharacterString>1540 30th St Campus Box 449</gco:CharacterString> </gmd:deliveryPoint> <gmd:city> <gco:CharacterString>Boulder</gco:CharacterString> </gmd:city> <gmd:administrativeArea> <gco:CharacterString>Colorado</gco:CharacterString> </gmd:administrativeArea> <gmd:postalCode> <gco:CharacterString>80309-0449</gco:CharacterString> </gmd:postalCode> <gmd:country> <gco:CharacterString>USA</gco:CharacterString> </gmd:country> <gmd:electronicMailAddress> <gco:CharacterString>nsidc@nsidc.org</gco:CharacterString> </gmd:electronicMailAddress> </gmd:CI_Address> </gmd:address> <gmd:onlineResource> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://nsidc.org/daac/</gmd:URL> </gmd:linkage> </gmd:CI_OnlineResource> </gmd:onlineResource> <gmd:hoursOfService> <gco:CharacterString>9:00 A.M. to 5:00 P.M., U.S. Mountain Time, Monday through Friday, excluding U.S. holidays.</gco:CharacterString> </gmd:hoursOfService> <gmd:contactInstructions> <gco:CharacterString>Contact by e-mail first</gco:CharacterString> </gmd:contactInstructions> </gmd:CI_Contact> </gmd:contactInfo> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:contact> <gmd:dateStamp> <gco:Date>2015-10-15</gco:Date> </gmd:dateStamp> <gmd:metadataStandardName> <gco:CharacterString>ISO 19115-2 Geographic information - Metadata - Part 2: Extensions for imagery and gridded data</gco:CharacterString> </gmd:metadataStandardName> <gmd:metadataStandardVersion> <gco:CharacterString>ISO 19115-2:2009(E)</gco:CharacterString> </gmd:metadataStandardVersion> <gmd:identificationInfo> <gmd:MD_DataIdentification> <gmd:citation> <gmd:CI_Citation> <!-- ECS extracts the LongName from here --> <!-- UMM-C expects the ShortName to precede the LongName separated by a &gt; here --> <gmd:title> <gco:CharacterString>ATLAS/ICESat-2 L2A Global Geolocated Photon Data</gco:CharacterString> </gmd:title> <gmd:date> <gmd:CI_Date> <!-- ECS extracts the RevisionDate from here --> <gmd:date> <gco:Date>2016-06-09</gco:Date> </gmd:date> <gmd:dateType> <gmd:CI_DateTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_DateTypeCode" codeListValue="revision">revision</gmd:CI_DateTypeCode> </gmd:dateType> </gmd:CI_Date> </gmd:date> <!-- VersionID is expected to be here by the Base Reference Metadata Model document --> <gmd:edition> <gco:CharacterString>003</gco:CharacterString> </gmd:edition> <gmd:identifier> <gmd:MD_Identifier> <!-- ECS extracts the ShortName from here --> <gmd:code> <gco:CharacterString>ATL03</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>The ECS Short Name</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> <gmd:identifier> <gmd:MD_Identifier> <!-- ECS extracts the VersionID from here --> <gmd:code> <gco:CharacterString>003</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>The ECS Version ID</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> <gmd:identifier> <gmd:MD_Identifier> <!-- This field provides the Digital Object Identifier (DOI). --> <gmd:code> <gmx:Anchor xlink:actuate="onRequest" xlink:href="http://dx.doi.org/10.5067/ATLAS/ATL03.003">doi:10.5067/ATLAS/ATL03.003</gmx:Anchor> </gmd:code> <gmd:codeSpace> <gco:CharacterString>gov.nasa.esdis</gco:CharacterString> </gmd:codeSpace> <gmd:description> <gco:CharacterString>A Digital Object Identifier (DOI)</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:identifier> <gmd:citedResponsibleParty> <gmd:CI_ResponsibleParty> <gmd:organisationName> <gco:CharacterString>National Aeronautics and Space Administration (NASA)</gco:CharacterString> </gmd:organisationName> <gmd:role> <gmd:CI_RoleCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="resourceProvider">resourceProvider</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:citedResponsibleParty> <gmd:citedResponsibleParty> <gmd:CI_ResponsibleParty> <!-- ECS expects ProcessingCenter to be here --> <gmd:organisationName> <gco:CharacterString>GSFC I-SIPS &gt; ICESat-2 Science Investigator-led Processing System</gco:CharacterString> </gmd:organisationName> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="originator">originator</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:citedResponsibleParty> <!-- ECS extracts the VersionDescription from here --> <gmd:otherCitationDetails> <gco:CharacterString>Initial version of the processing software</gco:CharacterString> </gmd:otherCitationDetails> </gmd:CI_Citation> </gmd:citation> <!-- ECS extracts the CollectionDescription from here --> <gmd:abstract> <gco:CharacterString>The ICESat-2 ATL03 standard data product contains precise latitude, longitude and height above ellipsoid for all received photons. Geophysical corrections are applied to the photon height values and each photon is classified as signal vs. background. Includes segmented data at a 20-meter along-track length. Geophysical corrections, atmosphere corrections and the surface types (land ice, sea ice, ocean, land, inland water) are provided for each 20-meter segment.</gco:CharacterString> </gmd:abstract> <gmd:purpose> <gco:CharacterString>The purpose of ATL03 is to provide along-track photon data for all 6 ATLAS beams and associated statistics.</gco:CharacterString> </gmd:purpose> <gmd:credit> <gco:CharacterString>The software that generates the ATL03 product was designed and implemented within the ICESat-2 Science Investigator-led Processing System at the NASA Goddard Space Flight Center in Greenbelt, Maryland.</gco:CharacterString> </gmd:credit> <gmd:status> <gmd:MD_ProgressCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ProgressCode" codeListValue="onGoing">onGoing</gmd:MD_ProgressCode> </gmd:status> <gmd:pointOfContact> <gmd:CI_ResponsibleParty> <!-- ECS expects ArchiveCenter to be here --> <gmd:organisationName> <gco:CharacterString>NSIDC DAAC &gt; NASA National Snow and Ice Data Center Distributed Active Archive Center</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo xlink:href="#NSIDC_DAAC_CONTACT_ID"/> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="distributor">distributor</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:pointOfContact> <gmd:resourceFormat> <gmd:MD_Format> <gmd:name> <gco:CharacterString>HDF</gco:CharacterString> </gmd:name> <gmd:version> <gco:CharacterString>5</gco:CharacterString> </gmd:version> </gmd:MD_Format> </gmd:resourceFormat> <gmd:descriptiveKeywords> <gmd:MD_Keywords> <gmd:keyword> <gco:CharacterString>EARTH SCIENCE &gt; CRYOSPHERE &gt; SEA ICE &gt; NONE &gt; NONE &gt; NONE &gt; NONE</gco:CharacterString> </gmd:keyword> <gmd:keyword> <gco:CharacterString>EARTH SCIENCE &gt; CRYOSPHERE &gt; GLACIERS/ICE SHEETS &gt; NONE &gt; NONE &gt; NONE &gt; NONE</gco:CharacterString> </gmd:keyword> <gmd:keyword> <gco:CharacterString>EARTH SCIENCE &gt; LAND SURFACE &gt; TOPOGRAPHY &gt; NONE &gt; NONE &gt; NONE &gt; NONE</gco:CharacterString> </gmd:keyword> <gmd:keyword> <gco:CharacterString>EARTH SCIENCE &gt; OCEANS &gt; SEA SURFACE TOPOGRAPHY &gt; NONE &gt; NONE &gt; NONE &gt; NONE</gco:CharacterString> </gmd:keyword> <gmd:type> <gmd:MD_KeywordTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode> </gmd:type> <gmd:thesaurusName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>NASA/GCMD Science Keywords</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:citedResponsibleParty> <gmd:CI_ResponsibleParty id="GCMD_USO_ID"> <gmd:organisationName> <gco:CharacterString>NASA Global Change Master Directory (GCMD) User Support Office</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo> <gmd:CI_Contact> <gmd:phone gco:nilReason="missing"/> <gmd:address> <gmd:CI_Address> <gmd:deliveryPoint> <gco:CharacterString>NASA Global Change Master Directory, Goddard Space Flight Center</gco:CharacterString> </gmd:deliveryPoint> <gmd:city> <gco:CharacterString>Greenbelt</gco:CharacterString> </gmd:city> <gmd:administrativeArea> <gco:CharacterString>MD</gco:CharacterString> </gmd:administrativeArea> <gmd:postalCode> <gco:CharacterString>20771</gco:CharacterString> </gmd:postalCode> <gmd:country> <gco:CharacterString>USA</gco:CharacterString> </gmd:country> <gmd:electronicMailAddress> <gco:CharacterString>gcmduso@gcmd.gsfc.nasa.gov</gco:CharacterString> </gmd:electronicMailAddress> </gmd:CI_Address> </gmd:address> <gmd:onlineResource> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://gcmd.nasa.gov/</gmd:URL> </gmd:linkage> <gmd:protocol> <gco:CharacterString>http</gco:CharacterString> </gmd:protocol> <gmd:applicationProfile> <gco:CharacterString>web browser</gco:CharacterString> </gmd:applicationProfile> <gmd:name> <gco:CharacterString>NASA Global Change Master Directory (GCMD)</gco:CharacterString> </gmd:name> <gmd:description> <gco:CharacterString>Home Page</gco:CharacterString> </gmd:description> <gmd:function> <gmd:CI_OnLineFunctionCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode> </gmd:function> </gmd:CI_OnlineResource> </gmd:onlineResource> <gmd:contactInstructions> <gco:CharacterString>http://gcmd.nasa.gov/MailComments/MailComments.jsf?rcpt=gcmduso</gco:CharacterString> </gmd:contactInstructions> </gmd:CI_Contact> </gmd:contactInfo> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="custodian">custodian</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:citedResponsibleParty> <gmd:citedResponsibleParty> <gmd:CI_ResponsibleParty id="GCMD_KEYWORDS_ID"> <gmd:organisationName> <gco:CharacterString>Global Change Master Directory (GCMD)</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo> <gmd:CI_Contact> <gmd:phone gco:nilReason="missing"/> <gmd:address> <gmd:CI_Address> <gmd:deliveryPoint> <gco:CharacterString>NASA Global Change Master Directory, Goddard Space Flight Center</gco:CharacterString> </gmd:deliveryPoint> <gmd:city> <gco:CharacterString>Greenbelt</gco:CharacterString> </gmd:city> <gmd:administrativeArea> <gco:CharacterString>MD</gco:CharacterString> </gmd:administrativeArea> <gmd:postalCode> <gco:CharacterString>20771</gco:CharacterString> </gmd:postalCode> <gmd:country> <gco:CharacterString>USA</gco:CharacterString> </gmd:country> <gmd:electronicMailAddress> <gco:CharacterString>gcmduso@gcmd.gsfc.nasa.gov</gco:CharacterString> </gmd:electronicMailAddress> </gmd:CI_Address> </gmd:address> <gmd:onlineResource> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://gcmd.nasa.gov/Resources/valids/</gmd:URL> </gmd:linkage> <gmd:protocol> <gco:CharacterString>http</gco:CharacterString> </gmd:protocol> <gmd:applicationProfile> <gco:CharacterString>web browser</gco:CharacterString> </gmd:applicationProfile> <gmd:name> <gco:CharacterString>NASA Global Change Master Directory (GCMD) Keyword Page</gco:CharacterString> </gmd:name> <gmd:description> <gco:CharacterString>This page describes the NASA GCMD Keywords, how to reference those keywords and provides download instructions.</gco:CharacterString> </gmd:description> <gmd:function> <gmd:CI_OnLineFunctionCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="download">download</gmd:CI_OnLineFunctionCode> </gmd:function> </gmd:CI_OnlineResource> </gmd:onlineResource> <gmd:contactInstructions> <gco:CharacterString>http://gcmd.nasa.gov/MailComments/MailComments.jsf?rcpt=gcmduso</gco:CharacterString> </gmd:contactInstructions> </gmd:CI_Contact> </gmd:contactInfo> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="custodian">custodian</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:citedResponsibleParty> </gmd:CI_Citation> </gmd:thesaurusName> </gmd:MD_Keywords> </gmd:descriptiveKeywords> <gmd:descriptiveKeywords> <gmd:MD_Keywords> <gmd:keyword> <gco:CharacterString>GEOGRAPHIC REGION &gt; GLOBAL</gco:CharacterString> </gmd:keyword> <gmd:type> <gmd:MD_KeywordTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="place">place</gmd:MD_KeywordTypeCode> </gmd:type> <gmd:thesaurusName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>NASA/GCMD Location Keywords</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:citedResponsibleParty xlink:href="#GCMD_USO_ID"/> <gmd:citedResponsibleParty xlink:href="#GCMD_KEYWORDS_ID"/> </gmd:CI_Citation> </gmd:thesaurusName> </gmd:MD_Keywords> </gmd:descriptiveKeywords> <gmd:descriptiveKeywords> <gmd:MD_Keywords> <gmd:keyword> <gco:CharacterString>NASA/NSIDC_DAAC &gt; NASA National Snow and Ice Data Center Distributed Active Archive Center</gco:CharacterString> </gmd:keyword> <gmd:type> <gmd:MD_KeywordTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="dataCenter">dataCenter</gmd:MD_KeywordTypeCode> </gmd:type> <gmd:thesaurusName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>NASA/GCMD Data Center Keywords</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:citedResponsibleParty xlink:href="#GCMD_USO_ID"/> <gmd:citedResponsibleParty xlink:href="#GCMD_KEYWORDS_ID"/> </gmd:CI_Citation> </gmd:thesaurusName> </gmd:MD_Keywords> </gmd:descriptiveKeywords> <gmd:descriptiveKeywords> <gmd:MD_Keywords> <gmd:keyword> <gco:CharacterString>Earth Observation Satellites &gt; NASA Decadal Survey &gt; ICESAT-2 &gt; Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmd:keyword> <gmd:type> <gmd:MD_KeywordTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="platform">platform</gmd:MD_KeywordTypeCode> </gmd:type> <gmd:thesaurusName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>NASA/GCMD Platform Keywords</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:citedResponsibleParty xlink:href="#GCMD_USO_ID"/> <gmd:citedResponsibleParty xlink:href="#GCMD_KEYWORDS_ID"/> </gmd:CI_Citation> </gmd:thesaurusName> </gmd:MD_Keywords> </gmd:descriptiveKeywords> <gmd:descriptiveKeywords> <gmd:MD_Keywords> <gmd:keyword> <gco:CharacterString>Earth Remote Sensing Instruments &gt; Active Remote Sensing &gt; Altimeters &gt; Lidar/Laser Altimeters &gt; ATLAS &gt; Advanced Topographic Laser Altimeter System</gco:CharacterString> </gmd:keyword> <gmd:type> <gmd:MD_KeywordTypeCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="instrument">instrument</gmd:MD_KeywordTypeCode> </gmd:type> <gmd:thesaurusName> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>NASA/GCMD Instrument Keywords</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> <gmd:citedResponsibleParty xlink:href="#GCMD_USO_ID"/> <gmd:citedResponsibleParty xlink:href="#GCMD_KEYWORDS_ID"/> </gmd:CI_Citation> </gmd:thesaurusName> </gmd:MD_Keywords> </gmd:descriptiveKeywords> <gmd:resourceConstraints> <gmd:MD_Constraints> <gmd:useLimitation> <gco:CharacterString>Cite these data in publications as follows: The data used in this study were produced by the ICESat-2 Science Project Office at NASA/GSFC. The data archive site is the NASA National Snow and Ice Data Center Distributed Active Archive Center.</gco:CharacterString> </gmd:useLimitation> </gmd:MD_Constraints> </gmd:resourceConstraints> <gmd:language> <gco:CharacterString>eng</gco:CharacterString> </gmd:language> <gmd:topicCategory> <gmd:MD_TopicCategoryCode>geoscientificInformation</gmd:MD_TopicCategoryCode> </gmd:topicCategory> <gmd:extent> <gmd:EX_Extent id="boundingExtent"> <gmd:description> <gco:CharacterString>SpatialCoverageType=HORIZONTAL, SpatialGranuleSpatialRepresentation=ORBIT, TemporalRangeType=Continuous Range, TimeType=UTC</gco:CharacterString> </gmd:description> <gmd:geographicElement> <gmd:EX_GeographicBoundingBox> <!-- ECS extracts WestBoundingCoordinate from here --> <gmd:westBoundLongitude> <gco:Decimal>-180.0</gco:Decimal> </gmd:westBoundLongitude> <!-- ECS extracts EastBoundingCoordinate from here --> <gmd:eastBoundLongitude> <gco:Decimal>180.0</gco:Decimal> </gmd:eastBoundLongitude> <!-- ECS extracts SouthBoundingCoordinate from here --> <gmd:southBoundLatitude> <gco:Decimal>-90.0</gco:Decimal> </gmd:southBoundLatitude> <!-- ECS extracts NorthBoundingCoordinate from here --> <gmd:northBoundLatitude> <gco:Decimal>90.0</gco:Decimal> </gmd:northBoundLatitude> </gmd:EX_GeographicBoundingBox> </gmd:geographicElement> <gmd:geographicElement> <gmd:EX_GeographicDescription> <gmd:geographicIdentifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>SwathWidth: 36.0 Period: 96.8 InclinationAngle: 92.0 NumberOfOrbits: 0.071428571 StartCircularLatitude: 0.0</gco:CharacterString> </gmd:code> <gmd:codeSpace> <gco:CharacterString>gov.nasa.esdis.umm.orbitparameters</gco:CharacterString> </gmd:codeSpace> <gmd:description> <gco:CharacterString>OrbitParameters</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmd:geographicIdentifier> </gmd:EX_GeographicDescription> </gmd:geographicElement> <gmd:temporalElement> <gmd:EX_TemporalExtent> <gmd:extent> <gml:TimePeriod gml:id="TimePeriod_ID_1"> <!-- ECS extracts RangeBeginningDate and RangeBeginningTime from here --> <gml:beginPosition>2005-01-01T00:00:00Z</gml:beginPosition> <!-- ECS extracts RangeEndingDate and RangeEndingTime from here --> <gml:endPosition>2020-12-31T23:59:59Z</gml:endPosition> </gml:TimePeriod> </gmd:extent> </gmd:EX_TemporalExtent> </gmd:temporalElement> </gmd:EX_Extent> </gmd:extent> <gmd:processingLevel> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>2A</gco:CharacterString> </gmd:code> <gmd:description gco:nilReason="missing"/> </gmd:MD_Identifier> </gmd:processingLevel> </gmd:MD_DataIdentification> </gmd:identificationInfo> <gmd:contentInfo> <gmd:MD_ImageDescription> <gmd:attributeDescription gco:nilReason="missing"/> <gmd:contentType gco:nilReason="missing"/> <gmd:processingLevelCode> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>2A</gco:CharacterString> </gmd:code> <gmd:description gco:nilReason="missing"/> </gmd:MD_Identifier> </gmd:processingLevelCode> </gmd:MD_ImageDescription> </gmd:contentInfo> <gmd:distributionInfo> <gmd:MD_Distribution> <gmd:distributionFormat> <gmd:MD_Format> <gmd:name> <gco:CharacterString>HDF</gco:CharacterString> </gmd:name> <gmd:version> <gco:CharacterString>5</gco:CharacterString> </gmd:version> </gmd:MD_Format> </gmd:distributionFormat> <gmd:distributor> <gmd:MD_Distributor> <gmd:distributorContact> <gmd:CI_ResponsibleParty> <gmd:organisationName> <gco:CharacterString>NSIDC DAAC &gt; NASA National Snow and Ice Data Center Distributed Active Archive Center</gco:CharacterString> </gmd:organisationName> <gmd:contactInfo xlink:href="#NSIDC_DAAC_CONTACT_ID"/> <gmd:role> <gmd:CI_RoleCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_RoleCode" codeListValue="distributor">distributor</gmd:CI_RoleCode> </gmd:role> </gmd:CI_ResponsibleParty> </gmd:distributorContact> <gmd:distributorTransferOptions> <gmd:MD_DigitalTransferOptions> <gmd:onLine> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://nsidc.org/data/icesat2/data.html</gmd:URL> </gmd:linkage> <gmd:protocol> <gco:CharacterString>http</gco:CharacterString> </gmd:protocol> <gmd:description> <gco:CharacterString>Data Product Description Page</gco:CharacterString> </gmd:description> <gmd:function> <gmd:CI_OnLineFunctionCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode> </gmd:function> </gmd:CI_OnlineResource> </gmd:onLine> <gmd:onLine> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://nsidc.org/data/icesat2/order.html</gmd:URL> </gmd:linkage> <gmd:protocol> <gco:CharacterString>http</gco:CharacterString> </gmd:protocol> <gmd:description> <gco:CharacterString>Data Product Order Page</gco:CharacterString> </gmd:description> <gmd:function> <gmd:CI_OnLineFunctionCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="order">order</gmd:CI_OnLineFunctionCode> </gmd:function> </gmd:CI_OnlineResource> </gmd:onLine> <gmd:onLine> <gmd:CI_OnlineResource> <gmd:linkage> <gmd:URL>http://dx.doi.org/10.5067/ATLAS/ATL03.003</gmd:URL> </gmd:linkage> <gmd:protocol> <gco:CharacterString>http</gco:CharacterString> </gmd:protocol> <gmd:description> <gco:CharacterString>Digital Object Identifier URL</gco:CharacterString> </gmd:description> <gmd:function> <gmd:CI_OnLineFunctionCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode> </gmd:function> </gmd:CI_OnlineResource> </gmd:onLine> </gmd:MD_DigitalTransferOptions> </gmd:distributorTransferOptions> </gmd:MD_Distributor> </gmd:distributor> </gmd:MD_Distribution> </gmd:distributionInfo> <gmi:acquisitionInformation> <gmi:MI_AcquisitionInformation> <gmi:instrument> <eos:EOS_Instrument id="ATLAS_INSTRUMENT_ID"> <gmi:citation> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>ATLAS &gt; Advanced Topographic Laser Altimeter System</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> </gmd:CI_Citation> </gmi:citation> <gmi:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>ATLAS</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>Advanced Topographic Laser Altimeter System</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmi:identifier> <gmi:type> <gco:CharacterString>Laser Altimeter</gco:CharacterString> </gmi:type> <gmi:description> <gco:CharacterString>ATLAS on ICESat-2 determines the range between the satellite and the Earth's surface by measuring the two-way time delay of short pulses of laser light that it transmits in six beams. It is different from previous operational ice-sheet altimeters in that it is a photon-counting LIDAR. ATLAS records a set of arrival times for individual photons, which are then analyzed to derive surface, vegetation, and cloud properties. ATLAS has six beams arranged in three pairs, so that it samples each of three reference pair tracks with a pair of beams; ATLAS transmits pulses at 10 kHz, giving approximately one pulse every 0.7 m along track; ATLAS's expected pointing control will be better than 90 m RMS.</gco:CharacterString> </gmi:description> <gmi:mountedOn xlink:href="#ICESAT_2_PLATFORM_ID"/> </eos:EOS_Instrument> </gmi:instrument> <gmi:operation> <!-- MI_Operation is expected to be here by the Base Reference Metadata Model document--> <gmi:MI_Operation> <gmi:description> <gco:CharacterString>ICESat-2 &gt; Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmi:description> <gmi:citation> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>ICESat-2 &gt; Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> </gmd:CI_Citation> </gmi:citation> <gmi:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>ICESat-2</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmi:identifier> <gmi:status> <gmd:MD_ProgressCode codeList="http://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_ProgressCode" codeListValue="underDevelopment">underDevelopment</gmd:MD_ProgressCode> </gmi:status> <gmi:parentOperation gco:nilReason="inapplicable"/> <gmi:platform xlink:href="#ICESAT_2_PLATFORM_ID"/> </gmi:MI_Operation> </gmi:operation> <gmi:platform> <eos:EOS_Platform id="ICESAT_2_PLATFORM_ID"> <gmi:citation> <gmd:CI_Citation> <gmd:title> <gco:CharacterString>ICESat-2 &gt; Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmd:title> <gmd:date gco:nilReason="unknown"/> </gmd:CI_Citation> </gmi:citation> <gmi:identifier> <gmd:MD_Identifier> <gmd:code> <gco:CharacterString>ICESat-2</gco:CharacterString> </gmd:code> <gmd:description> <gco:CharacterString>Ice, Cloud, and land Elevation Satellite-2</gco:CharacterString> </gmd:description> </gmd:MD_Identifier> </gmi:identifier> <gmi:description> <gco:CharacterString>Spacecraft</gco:CharacterString> </gmi:description> <gmi:instrument xlink:href="#ATLAS_INSTRUMENT_ID"/> </eos:EOS_Platform> </gmi:platform> </gmi:MI_AcquisitionInformation> </gmi:acquisitionInformation> </gmi:MI_Metadata> </gmd:seriesMetadata> </gmd:DS_Series> (Type is String)
  • AcquisitionInformation(Type is Group)
    no attributes
    • lidar(Type is Group)
      • attributes
        • pulse_rate: 10000 pps (Type is String)
        • wavelength: 532 nm (Type is String)
        • identifier: ATLAS (Type is String)
        • type: Laser Altimeter (Type is String)
        • description: ATLAS on ICESat-2 determines the range between the satellite and the Earth's surface by measuring the two-way time delay of short pulses of laser light that it transmits in six beams. It is different from previous operational ice-sheet altimeters in that it is a photon-counting LIDAR. ATLAS records a set of arrival times for individual photons, which are then analyzed to derive surface, vegetation, and cloud properties. ATLAS has six beams arranged in three pairs, so that it samples each of three reference pair tracks with a pair of beams; ATLAS transmits pulses at 10 kHz, giving approximately one pulse every 0.7 m along track; ATLAS's expected pointing control will be better than 90 m RMS. (Type is String)
    • lidarDocument(Type is Group)
      • attributes
        • edition: Pre-Release (Type is String)
        • publicationDate: 12/31/17 (Type is String)
        • title: A document describing the ATLAS instrument will be provided by the ICESat-2 Project Science Office. (Type is String)
    • platform(Type is Group)
      • attributes
        • identifier: ICESat-2 (Type is String)
        • description: Ice, Cloud, and land Elevation Satellite-2 (Type is String)
        • type: Spacecraft (Type is String)
    • platformDocument(Type is Group)
      • attributes
        • edition: 31-Dec-16 (Type is String)
        • publicationDate: 31-Dec-16 (Type is String)
        • title: The Ice, Cloud, and land Elevation Satellite-2 (ICESat-2): Science requirements, concept, and implementation. Thorsten Markus, Tom Neumann, Anthony Martino, Waleed Abdalati, Kelly Brunt, Beata Csatho, Sinead Farrell, Helen Fricker, Alex Gardner, David Harding, Michael Jasinski, Ron Kwok, Lori Magruder, Dan Lubin, Scott Luthcke, James Morison, Ross Nelson, Amy Neuenschwander, Stephen Palm, Sorin Popescu, CK Shum, Bob E. Schutz, Benjamin Smith, Yuekui Yang, Jay Zwally. http://dx.doi.org/10.1016/j.rse.2016.12.029 (Type is String)
  • DataQuality(Type is Group)
    • attributes
      • scope: NOT_SET (Type is String)
    • CompletenessOmission(Type is Group)
      • attributes
        • evaluationMethodType: directInternal (Type is String)
        • measureDescription: TBD (Type is String)
        • nameOfMeasure: TBD (Type is String)
        • unitofMeasure: TBD (Type is String)
        • value: NOT_SET (Type is String)
    • DomainConsistency(Type is Group)
      • attributes
        • evaluationMethodType: directInternal (Type is String)
        • measureDescription: TBD (Type is String)
        • nameOfMeasure: TBD (Type is String)
        • unitofMeasure: TBD (Type is String)
        • value: NOT_SET (Type is String)
  • ProductSpecificationDocument(Type is Group)
    • attributes
      • ShortName: ATL03_SDP (Type is String)
      • characterSet: utf8 (Type is String)
      • edition: v3.3 (Type is String)
      • language: eng (Type is String)
      • publicationDate: Feb 2020 (Type is String)
      • title: ICESat-2-SIPS-SPEC-4258 - ATLAS Science Algorithm Standard Data Product (SDP) Volume 3 (ATL03) (Type is String)
  • SeriesIdentification(Type is Group)
    • attributes
      • maintenanceAndUpdateFrequency: asNeeded (Type is String)
      • maintenanceDate: SET_BY_META (Type is String)
      • VersionID: 003 (Type is String)
      • language: eng (Type is String)
      • characterSet: utf8 (Type is String)
      • pointOfContact: NSIDC DAAC > NASA National Snow and Ice Data Center Distributed Active Archive Center (Type is String)
      • longName: ATLAS/ICESat-2 L2A Global Geolocated Photon Data (Type is String)
      • shortName: ATL03 (Type is String)
      • identifier_product_DOI: doi:10.5067/ATLAS/ATL03.003 (Type is String)
      • revisionDate: 2016-06-09 (Type is String)
      • resourceProviderOrganizationName: National Aeronautics and Space Administration (NASA) (Type is String)
      • abstract: The ICESat-2 ATL03 standard data product contains precise latitude, longitude and height above ellipsoid for all received photons. Geophysical corrections are applied to the photon height values and each photon is classified as signal vs. background. Includes segmented data at a 20-meter along-track length. Geophysical corrections, atmosphere corrections and the surface types (land ice, sea ice, ocean, land, inland water) are provided for each 20-meter segment. (Type is String)
      • purpose: The purpose of ATL03 is to provide along-track photon data for all 6 ATLAS beams and associated statistics. (Type is String)
      • credit: The software that generates the ATL03 product was designed and implemented within the ICESat-2 Science Investigator-led Processing System at the NASA Goddard Space Flight Center in Greenbelt, Maryland. (Type is String)
      • status: onGoing (Type is String)
      • format: HDF (Type is String)
      • formatVersion: 5 (Type is String)
      • topicCategory: geoscientificInformation (Type is String)
      • mission: ICESat-2 > Ice, Cloud, and land Elevation Satellite-2 (Type is String)
  • DatasetIdentification(Type is Group)
    • attributes
      • spatialRepresentationType: along-track (Type is String)
      • creationDate: 2020-03-21T12:54:34.000000Z (Type is String)
      • uuid: 5a847446-832e-3206-8ca9-8a632e4d761b (Type is String)
      • fileName: ATL03_20181228015957_13810110_003_01.h5 (Type is String)
      • VersionID: 003 (Type is String)
      • language: eng (Type is String)
      • characterSet: utf8 (Type is String)
      • shortName: ATL03 (Type is String)
      • originatorOrganizationName: GSFC I-SIPS > ICESat-2 Science Investigator-led Processing System (Type is String)
      • abstract: The ICESat-2 ATL03 standard data product contains precise latitude, longitude and height above ellipsoid for all received photons. Geophysical corrections are applied to the photon height values and each photon is classified as signal vs. background. Includes segmented data at a 20-meter along-track length. Geophysical corrections, atmosphere corrections and the surface types (land ice, sea ice, ocean, land, inland water) are provided for each 20-meter segment. (Type is String)
      • purpose: The purpose of ATL03 is to provide along-track photon data for all 6 ATLAS beams and associated statistics. (Type is String)
      • credit: The software that generates the ATL03 product was designed and implemented within the ICESat-2 Science Investigator-led Processing System at the NASA Goddard Space Flight Center in Greenbelt, Maryland. (Type is String)
      • status: onGoing (Type is String)
      • topicCategory: geoscientificInformation (Type is String)
  • Extent(Type is Group)
    • attributes
      • northBoundLatitude: -50.209962155122966 (Type is Float64)
      • eastBoundLongitude: -32.276188773376937 (Type is Float64)
      • southBoundLatitude: -79.002441705550709 (Type is Float64)
      • westBoundLongitude: -42.33993820187478 (Type is Float64)
      • rangeBeginningDateTime: 2018-12-28T02:00:01.217090Z (Type is String)
      • rangeEndingDateTime: 2018-12-28T02:07:38.713000Z (Type is String)
  • QADatasetIdentification(Type is Group)
    • attributes
      • abstract: An ASCII product that contains statistical information on data product results. These statistics enable data producers and users to assess the quality of the data in the data product granule (Type is String)
      • creationDate: 2020-03-21T13:10:59.000000Z (Type is String)
      • fileName: ATL03_20181228015957_13810110_003_01.qa (Type is String)
  • Lineage(Type is Group)
    no attributes
    • ANC25-03(Type is Group)
      • attributes
        • description: HDF5 template file that defines the organization and default content of the product. (Type is String)
        • fileName: ANC25-03_20200311165637_033_01.h5 (Type is String)
        • shortName: ANC25-03 (Type is String)
        • uuid: 70da5ea3-ba66-3521-a522-4b4fd7b72019 (Type is String)
        • version: 033 (Type is String)
    • ANC03(Type is Group)
      • attributes
        • description: ECI to ECF Quaternions file created by the ICESat-2 POD/PPD facility. (Type is String)
        • fileName: ANC03_f_201836200000_v01.h5 (Type is String)
        • shortName: ANC03 (Type is String)
        • uuid: fa210535-7efc-34c0-bc2a-a43ec0541563 (Type is String)
        • version: 005 (Type is String)
    • Control(Type is Group)
      • attributes
        • description: Text-based keyword=value file generated automatically within the ICESat-2 data system that specifies all of the conditions required for each individual run of the software. (Type is String)
        • fileName: CTL_atlas_l2a_alt_003449451.ctl (Type is String)
        • shortName: CNTL (Type is String)
        • version: 1 (Type is String)
    • ANC28(Type is Group)
      • attributes
        • description: DTU Mean Sea Surface re-referenced to the WGS84 ellipsoid. (Type is String)
        • fileName: dtu13_20180705_001_01.nc (Type is String)
        • shortName: ANC28 (Type is String)
        • uuid: 56f47040-a72e-3109-99c2-bc1658e6dda4 (Type is String)
        • version: 20180705 (Type is String)
    • ANC12-02(Type is Group)
      • attributes
        • description: ICESat-2 inland water mask, reformatted into HDF5. (Type is String)
        • fileName: iwmask_20200110_001_01.h5 (Type is String)
        • shortName: ANC12-02 (Type is String)
        • uuid: a5fed2a1-6b4f-3392-96e2-b0cb1fccce51 (Type is String)
        • version: 20200110 (Type is String)
    • ANC41(Type is Group)
      • attributes
        • description: Contains transmit pulse information derived from an aggregation of Transmit Echo Pulse (TEP) photons. (Type is String)
        • fileName: ANC41_20181227184238_13770101_003_01.h5 (Type is String)
        • shortName: ANC41 (Type is String)
        • uuid: ec177b30-41fc-3adf-a76a-827d5eee3a52 (Type is String)
        • version: 003 (Type is String)
        • start_cycle: 1 (Type is Int32)
        • end_cycle: 1 (Type is Int32)
        • start_orbit: 1578 (Type is Int32)
        • end_orbit: 1588 (Type is Int32)
        • start_rgt: 1377 (Type is Int32)
        • end_rgt: 1387 (Type is Int32)
        • start_region: 1 (Type is Int32)
        • end_region: 14 (Type is Int32)
    • ANC08(Type is Group)
      • attributes
        • description: Pole position file, provided by POD/PPD. (Type is String)
        • fileName: master_bih.table_20200131 (Type is String)
        • shortName: ANC08 (Type is String)
        • uuid: NOT_SET (Type is String)
        • version: 0 (Type is String)
    • ANC06-02(Type is Group)
      • attributes
        • description: ArcticDEM 32m Digital Elevation Model reformatted into HDF5. (Type is String)
        • fileName: arcticdem32m_20190611_001_01.h5 (Type is String)
        • shortName: ANC06-02 (Type is String)
        • uuid: ce07ef72-0bf4-353b-8475-fb568b029905 (Type is String)
        • version: 20190611 (Type is String)
    • ANC06-03(Type is Group)
      • attributes
        • description: REMA Antarctica 100m Digital Elevation Model filled and reformatted into HDF5 (Type is String)
        • fileName: atl06rema100m_20190628_001_01.h5 (Type is String)
        • shortName: ANC06-03 (Type is String)
        • uuid: 3e0a81bd-bbd5-35fa-b868-3254f9355b7f (Type is String)
        • version: 20190628 (Type is String)
    • ANC22(Type is Group)
      • attributes
        • description: Reference groundtrack file created by the ICESat-2 POD/PPD facility. (Type is String)
        • fileName: ANC22_201613900000_v01.h5 (Type is String)
        • shortName: ANC22 (Type is String)
        • uuid: 4b903e42-ed97-3176-bd96-151ff9ecc6fe (Type is String)
        • version: 001 (Type is String)
    • ANC11(Type is Group)
      • attributes
        • description: GOT 4.8 Ocean Tide coefficients, reformatted into HDF5. (Type is String)
        • fileName: anc_got_20160613_02.h5 (Type is String)
        • shortName: ANC11 (Type is String)
        • uuid: 747924e0-ca70-3e77-b664-0b2230118885 (Type is String)
        • version: 20160613 (Type is String)
    • ANC04(Type is Group)
      • attributes
        • description: Ephemeris file created by the ICESat-2 POD/PPD facility (Type is String)
        • fileName: ANC04_f_201836200000_v02.h5 (Type is String)
        • shortName: ANC04 (Type is String)
        • uuid: 744c3bb7-da77-37cc-97f4-f019731043dc (Type is String)
        • version: 005 (Type is String)
    • ANC38-03(Type is Group)
      • attributes
        • description: ISO 19139 XML file containing DataSet-level metadata information. (Type is String)
        • fileName: ANC38-03_20200311164501_003_01.xml (Type is String)
        • shortName: ANC38-03 (Type is String)
        • uuid: 76340bc9-ea1a-3a04-9d71-1a45225de4e0 (Type is String)
        • version: 003 (Type is String)
    • ANC01(Type is Group)
      • attributes
        • description: GEOS5-FPIT meteorological data files (retrieved from the GSFC DAAC) (Type is String)
        • fileName: GEOS.fpit.asm.inst3_3d_asm_Nv.GEOS5124.20181227_2100.V01.nc4, GEOS.fpit.asm.inst3_3d_asm_Nv.GEOS5124.20181228_0000.V01.nc4, GEOS.fpit.asm.inst3_3d_asm_Nv.GEOS5124.20181228_0300.V01.nc4 (Type is String)
        • shortName: ANC01, ANC01, ANC01 (Type is String)
        • uuid: edd6a055-0ef2-3e70-bdbd-de28bdd4c254, f6f6cc61-8c3d-37a1-8031-ae62be0ec3cf, 03b068b0-c9d7-39b9-ba82-850453342430 (Type is String)
        • version: 001, 001, 001 (Type is String)
    • ANC29(Type is Group)
      • attributes
        • description: Ocean Pole Load Tide coefficients (Type is String)
        • fileName: opoleloadcoefcmcor.h5 (Type is String)
        • shortName: ANC29 (Type is String)
        • uuid: 73eac247-556f-3810-b698-551bc4f8970f (Type is String)
        • version: 001 (Type is String)
    • ANC12-01(Type is Group)
      • attributes
        • description: ICESat-2 surface mask, reformatted into HDF5. (Type is String)
        • fileName: surfmask_20180608_001_01.h5 (Type is String)
        • shortName: ANC12-01 (Type is String)
        • uuid: 47683fac-2256-308c-b07e-71fb8b68f85d (Type is String)
        • version: 20180608 (Type is String)
    • ANC05(Type is Group)
      • attributes
        • description: LF_PNTG File created by the iCESat-2 POD/PPD facility. (Type is String)
        • fileName: ANC05_f_201836200000_v02_cal05_j2000.a.h5 (Type is String)
        • shortName: ANC05 (Type is String)
        • uuid: 0c412842-f845-3188-a825-f3d5d8b86d0d (Type is String)
        • version: 005 (Type is String)
    • ANC06-01(Type is Group)
      • attributes
        • description: GMTED 7.5 arcsec Digital Elevation Model reformatted into HDF5 and re-referenced to the WGS-84 ellipsoid. (Type is String)
        • fileName: gmted75_20180705_001_01.h5 (Type is String)
        • shortName: ANC06-01 (Type is String)
        • uuid: a44debc8-29af-3744-860c-227b37a4da6f (Type is String)
        • version: 20180705 (Type is String)
    • ANC36-03(Type is Group)
      • attributes
        • description: ISO 19139 XML file containing Series-level metadata information. (Type is String)
        • fileName: ANC36-03_20200311164459_003_01.xml (Type is String)
        • shortName: ANC36-03 (Type is String)
        • uuid: 6ae4e086-bcb6-3161-85a3-7a420a17f044 (Type is String)
        • version: 003 (Type is String)
    • ANC07(Type is Group)
      • attributes
        • description: EGM2008 geoid file, reformatted into HDF5. (Type is String)
        • fileName: egm2008_20140217_001_01.h5 (Type is String)
        • shortName: ANC07 (Type is String)
        • uuid: ed3b6888-0974-34bc-be2d-39e9c6fc1172 (Type is String)
        • version: 20140217 (Type is String)
    • ANC26-03(Type is Group)
      • attributes
        • description: HDF5 template file that defines the organization and default content of the product metadata. (Type is String)
        • fileName: ANC26-03_20200311165645_033_01.h5 (Type is String)
        • shortName: ANC26-03 (Type is String)
        • uuid: ba390f4a-d52f-3aef-a776-7009ebbb0081 (Type is String)
        • version: 033 (Type is String)
    • ATL02(Type is Group)
      • attributes
        • description: ATLAS/ICESat-2 L1B Converted Telemetry Data (Type is String)
        • end_geoseg: SET_BY_PGE (Type is String)
        • start_geoseg: SET_BY_PGE (Type is String)
        • fileName: ATL02_20181228015355_13810109_003_01.h5, ATL02_20181228015957_13810110_003_01.h5, ATL02_20181228020738_13810111_003_01.h5 (Type is String)
        • shortName: ATL02, ATL02, ATL02 (Type is String)
        • uuid: 86dbc3e7-3614-3641-99ab-d841185aebe8, d867c74d-a58b-3e2a-bc0b-4ade3a9b42c2, ae83baf3-fb84-3a87-963c-fb868d7bf553 (Type is String)
        • version: 003, 003, 003 (Type is String)
        • start_cycle: 1, 1, 1 (Type is Int32)
        • end_cycle: 1, 1, 1 (Type is Int32)
        • start_orbit: 1582, 1582, 1582 (Type is Int32)
        • end_orbit: 1582, 1582, 1582 (Type is Int32)
        • start_rgt: 1381, 1381, 1381 (Type is Int32)
        • end_rgt: 1381, 1381, 1381 (Type is Int32)
        • start_region: 9, 10, 11 (Type is Int32)
        • end_region: 9, 10, 11 (Type is Int32)
    • ANC19(Type is Group)
      • attributes
        • description: TAI to UTC leapsecond file retrieved from ftp://maia.usno.navy.mil/ser7/tai-utc.dat (Type is String)
        • fileName: tai_utc_2017.dat (Type is String)
        • shortName: ANC19 (Type is String)
        • uuid: 7c66d365-278a-31f7-8fe4-9c80e2f012e5 (Type is String)
        • version: 001 (Type is String)
    • ANC23(Type is Group)
      • attributes
        • description: Dynamic Atmosphere Correction File retrieved from CNES. (Type is String)
        • fileName: dac_dif_25197_18.nc, dac_dif_25198_00.nc, dac_dif_25198_06.nc (Type is String)
        • shortName: ANC23, ANC23, ANC23 (Type is String)
        • uuid: f6e93ab7-0e4d-3e6e-9fb4-4f9f9ccd1eec, 9f770a15-9a8a-37ab-9b9d-50a6dbcac261, 49733152-24f2-3a28-a63e-ff8a536e2509 (Type is String)
        • version: nc, nc, nc (Type is String)
  • ProcessStep(Type is Group)
    no attributes
    • Browse(Type is Group)
      • attributes
        • processDescription: Browse processing is performed for each granule SIPS produces. The browse utility reads data from the granule and produces browse images as defined in the respective product ATBD. The utility then embeds each browse image into the product within the /Browse group. (Type is String)
        • identifier: atlas_brw (Type is String)
        • softwareVersion: Version 2.3 (Type is String)
        • softwareDate: Feb 14 2020 (Type is String)
        • softwareTitle: Creates ATLAS HDF5 browse files (Type is String)
        • runTimeParameters: CTL_atlas_l2a_alt_003449451.ctl (Type is String)
        • stepDateTime: 2020-03-21T13:11:43.000000Z (Type is String)
    • Metadata(Type is Group)
      • attributes
        • processDescription: Metadata information is processed by the metadata utility for each granule produced by SIPS. During PGE processing, dynamic metadata are written to the product. Additional static information is provided with the metadata template. The metadata utility reads ISO Dataset and Series metadata files and updates the product with static information from within those files. The utility then merges the static and dynamic metadata to creates output ISO19139 Dataset and Series XML files. Finally the utility reads the ISO19139 Dataset and Series XML files into memory and stores the textual representations as attributes attached to the /METADATA group. (Type is String)
        • identifier: atlas_meta (Type is String)
        • softwareVersion: Version 4.3 (Type is String)
        • softwareDate: Feb 3 2020 (Type is String)
        • softwareTitle: Creates ATLAS XML metadata files (Type is String)
        • runTimeParameters: CTL_atlas_l2a_alt_003449451.ctl (Type is String)
        • stepDateTime: 2020-03-21T13:12:24.000000Z (Type is String)
    • PGE(Type is Group)
      • attributes
        • ATBDDate: 12/20/2019 (Type is String)
        • ATBDTitle: Algorithm Theoretical Basis Document (ATBD) for Global Geolocated Photons ATL03 (Type is String)
        • ATBDVersion: v.2 (Type is String)
        • documentDate: Feb 2020 (Type is String)
        • documentation: ATLAS Science Algorithm Software Design Description (SDD) - Volume 7 (atlas_l2a_alt) (Type is String)
        • processDescription: The atlas_l2a_alt PGE geolocates individual photon returns, performs signal classification and applies geophysical corrections to individual photon heights. (Type is String)
        • identifier: atlas_l2a_alt (Type is String)
        • softwareVersion: Version 3.3 (Type is String)
        • softwareDate: Feb 3 2020 (Type is String)
        • softwareTitle: ASAS L2A ALT PGE (Type is String)
        • runTimeParameters: CTL_atlas_l2a_alt_003449451.ctl (Type is String)
        • stepDateTime: 2020-03-21T12:54:34.000000Z (Type is String)
    • QA(Type is Group)
      • attributes
        • processDescription: QA processing is performed by an external utility on each granule produced by SIPS. The utility reads the granule, performs both generic and product-specific quality-assessment calculations, and writes a text-based quality assessment report. The name and creation data of this report are identified within the QADatasetIdentification metadata (Type is String)
        • identifier: atl03_qa_util (Type is String)
        • softwareVersion: Version 3.3 (Type is String)
        • softwareDate: Feb 3 2020 (Type is String)
        • softwareTitle: ATL03 QA Utility (Type is String)
        • runTimeParameters: CTL_atlas_l2a_alt_003449451.ctl (Type is String)
        • stepDateTime: 2020-03-21T13:10:59.000000Z (Type is String)
gt1r(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce3 (Type is String)
    • atlas_beam_type: strong (Type is String)
    • groundtrack_id: gt1r (Type is String)
    • atmosphere_profile: profile_1 (Type is String)
    • atlas_spot_number: 5 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt1r/bckgrd_atlas/delta_time = 0..89489 ]
    • delta_time[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt1r/bckgrd_atlas/delta_time= 0..89489] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt1r/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt1r/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt1r/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt1r/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt1r/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt1r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt1r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt1r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt1r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt1r/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt1r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1r/signal_find_output/sea_ice/delta_time = 0..62224 ]
      • delta_time[ /gt1r/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1r/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1r/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1r/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1r/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1r/signal_find_output/land/delta_time = 0..5225 ]
      • delta_time[ /gt1r/signal_find_output/land/delta_time= 0..5225] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1r/signal_find_output/land/delta_time= 0..5225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1r/signal_find_output/land/delta_time= 0..5225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1r/signal_find_output/land/delta_time= 0..5225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1r/signal_find_output/land/delta_time= 0..5225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1r/signal_find_output/ocean/delta_time = 0..72325 ]
      • delta_time[ /gt1r/signal_find_output/ocean/delta_time= 0..72325] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1r/signal_find_output/ocean/delta_time= 0..72325] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1r/signal_find_output/ocean/delta_time= 0..72325] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1r/signal_find_output/ocean/delta_time= 0..72325] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1r/signal_find_output/ocean/delta_time= 0..72325] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1r/signal_find_output/land_ice/delta_time = 0..18587 ]
      • delta_time[ /gt1r/signal_find_output/land_ice/delta_time= 0..18587] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1r/signal_find_output/land_ice/delta_time= 0..18587] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1r/signal_find_output/land_ice/delta_time= 0..18587] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1r/signal_find_output/land_ice/delta_time= 0..18587] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1r/signal_find_output/land_ice/delta_time= 0..18587] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1r/signal_find_output/inlandwater/delta_time = 0..16566 ]
      • delta_time[ /gt1r/signal_find_output/inlandwater/delta_time= 0..16566] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1r/signal_find_output/inlandwater/delta_time= 0..16566] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1r/signal_find_output/inlandwater/delta_time= 0..16566] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1r/signal_find_output/inlandwater/delta_time= 0..16566] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1r/signal_find_output/inlandwater/delta_time= 0..16566] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt1r/heights/delta_time = 0..4102520 ]
    • delta_time[ /gt1r/heights/delta_time= 0..4102520] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt1r/heights/delta_time= 0..4102520] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt1r/heights/delta_time= 0..4102520] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt1r/heights/delta_time= 0..4102520] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt1r/heights/delta_time= 0..4102520] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt1r/heights/delta_time= 0..4102520] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt1r/heights/delta_time= 0..4102520] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt1r/heights/delta_time= 0..4102520] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt1r/heights/delta_time= 0..4102520] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt1r/heights/delta_time= 0..4102520] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt1r/heights/delta_time= 0..4102520] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
gt2r(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce2 (Type is String)
    • atlas_beam_type: strong (Type is String)
    • groundtrack_id: gt2r (Type is String)
    • atmosphere_profile: profile_2 (Type is String)
    • atlas_spot_number: 3 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt2r/bckgrd_atlas/delta_time = 0..91494 ]
    • delta_time[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt2r/bckgrd_atlas/delta_time= 0..91494] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt2r/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt2r/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt2r/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt2r/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt2r/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt2r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt2r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt2r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt2r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt2r/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt2r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2r/signal_find_output/ocean/delta_time = 0..72580 ]
      • delta_time[ /gt2r/signal_find_output/ocean/delta_time= 0..72580] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2r/signal_find_output/ocean/delta_time= 0..72580] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2r/signal_find_output/ocean/delta_time= 0..72580] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2r/signal_find_output/ocean/delta_time= 0..72580] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2r/signal_find_output/ocean/delta_time= 0..72580] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2r/signal_find_output/sea_ice/delta_time = 0..62143 ]
      • delta_time[ /gt2r/signal_find_output/sea_ice/delta_time= 0..62143] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2r/signal_find_output/sea_ice/delta_time= 0..62143] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2r/signal_find_output/sea_ice/delta_time= 0..62143] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2r/signal_find_output/sea_ice/delta_time= 0..62143] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2r/signal_find_output/sea_ice/delta_time= 0..62143] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2r/signal_find_output/land_ice/delta_time = 0..18664 ]
      • delta_time[ /gt2r/signal_find_output/land_ice/delta_time= 0..18664] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2r/signal_find_output/land_ice/delta_time= 0..18664] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2r/signal_find_output/land_ice/delta_time= 0..18664] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2r/signal_find_output/land_ice/delta_time= 0..18664] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2r/signal_find_output/land_ice/delta_time= 0..18664] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2r/signal_find_output/land/delta_time = 0..5248 ]
      • delta_time[ /gt2r/signal_find_output/land/delta_time= 0..5248] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2r/signal_find_output/land/delta_time= 0..5248] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2r/signal_find_output/land/delta_time= 0..5248] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2r/signal_find_output/land/delta_time= 0..5248] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2r/signal_find_output/land/delta_time= 0..5248] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2r/signal_find_output/inlandwater/delta_time = 0..16706 ]
      • delta_time[ /gt2r/signal_find_output/inlandwater/delta_time= 0..16706] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2r/signal_find_output/inlandwater/delta_time= 0..16706] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2r/signal_find_output/inlandwater/delta_time= 0..16706] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2r/signal_find_output/inlandwater/delta_time= 0..16706] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2r/signal_find_output/inlandwater/delta_time= 0..16706] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt2r/heights/delta_time = 0..3646223 ]
    • delta_time[ /gt2r/heights/delta_time= 0..3646223] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt2r/heights/delta_time= 0..3646223] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt2r/heights/delta_time= 0..3646223] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt2r/heights/delta_time= 0..3646223] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt2r/heights/delta_time= 0..3646223] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt2r/heights/delta_time= 0..3646223] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt2r/heights/delta_time= 0..3646223] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt2r/heights/delta_time= 0..3646223] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt2r/heights/delta_time= 0..3646223] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt2r/heights/delta_time= 0..3646223] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt2r/heights/delta_time= 0..3646223] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
gt1l(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce3 (Type is String)
    • atlas_beam_type: weak (Type is String)
    • groundtrack_id: gt1l (Type is String)
    • atmosphere_profile: profile_1 (Type is String)
    • atlas_spot_number: 6 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt1l/bckgrd_atlas/delta_time = 0..84273 ]
    • delta_time[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt1l/bckgrd_atlas/delta_time= 0..84273] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt1l/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt1l/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt1l/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt1l/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt1l/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt1l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt1l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt1l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt1l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt1l/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt1l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1l/signal_find_output/land/delta_time = 0..4201 ]
      • delta_time[ /gt1l/signal_find_output/land/delta_time= 0..4201] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1l/signal_find_output/land/delta_time= 0..4201] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1l/signal_find_output/land/delta_time= 0..4201] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1l/signal_find_output/land/delta_time= 0..4201] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1l/signal_find_output/land/delta_time= 0..4201] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1l/signal_find_output/ocean/delta_time = 0..61612 ]
      • delta_time[ /gt1l/signal_find_output/ocean/delta_time= 0..61612] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1l/signal_find_output/ocean/delta_time= 0..61612] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1l/signal_find_output/ocean/delta_time= 0..61612] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1l/signal_find_output/ocean/delta_time= 0..61612] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1l/signal_find_output/ocean/delta_time= 0..61612] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1l/signal_find_output/sea_ice/delta_time = 0..62224 ]
      • delta_time[ /gt1l/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1l/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1l/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1l/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1l/signal_find_output/sea_ice/delta_time= 0..62224] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1l/signal_find_output/land_ice/delta_time = 0..10277 ]
      • delta_time[ /gt1l/signal_find_output/land_ice/delta_time= 0..10277] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1l/signal_find_output/land_ice/delta_time= 0..10277] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1l/signal_find_output/land_ice/delta_time= 0..10277] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1l/signal_find_output/land_ice/delta_time= 0..10277] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1l/signal_find_output/land_ice/delta_time= 0..10277] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt1l/signal_find_output/inlandwater/delta_time = 0..4332 ]
      • delta_time[ /gt1l/signal_find_output/inlandwater/delta_time= 0..4332] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt1l/signal_find_output/inlandwater/delta_time= 0..4332] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt1l/signal_find_output/inlandwater/delta_time= 0..4332] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt1l/signal_find_output/inlandwater/delta_time= 0..4332] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt1l/signal_find_output/inlandwater/delta_time= 0..4332] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt1l/heights/delta_time = 0..2923410 ]
    • delta_time[ /gt1l/heights/delta_time= 0..2923410] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt1l/heights/delta_time= 0..2923410] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt1l/heights/delta_time= 0..2923410] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt1l/heights/delta_time= 0..2923410] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt1l/heights/delta_time= 0..2923410] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt1l/heights/delta_time= 0..2923410] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt1l/heights/delta_time= 0..2923410] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt1l/heights/delta_time= 0..2923410] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt1l/heights/delta_time= 0..2923410] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt1l/heights/delta_time= 0..2923410] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt1l/heights/delta_time= 0..2923410] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
quality_assessment(Type is Group)
  • attributes
    • Description: Contains quality assessment data. This may include QA counters, QA along-track data and/or QA summary data. (Type is String)
Dimensions: [ /quality_assessment/delta_time = 0..0 ]
  • delta_time[ /quality_assessment/delta_time= 0..0] (Type is Float64)
    • attributes
      • contentType: referenceInformation (Type is String)
      • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
      • long_name: Elapsed GPS seconds (Type is String)
      • source: Operations (Type is String)
      • standard_name: time (Type is String)
      • units: seconds since 2018-01-01 (Type is String)
  • qa_granule_fail_reason[ 0..0] (Type is Int32)
    • attributes
      • contentType: qualityInformation (Type is String)
      • description: Flag indicating granule failure reason. 0=no failure; 1=processing error; 2=Insufficient output data was generated; 3=TBD Failure; 4=TBD_Failure; 5=other failure. (Type is String)
      • flag_meanings: no_failure PROCESS_ERROR INSUFFICIENT_OUTPUT failure_3 failure_4 OTHER_FAILURE (Type is String)
      • flag_values: 0, 1, 2, 3, 4, 5 (Type is Int32)
      • long_name: Granule Failure Reason (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
      • valid_max: 5 (Type is Int32)
      • valid_min: 0 (Type is Int32)
  • qa_granule_pass_fail[ 0..0] (Type is Int32)
    • attributes
      • contentType: qualityInformation (Type is String)
      • description: Flag indicating granule quality. 0=granule passes automatic QA. 1=granule fails automatic QA. (Type is String)
      • flag_meanings: PASS FAIL (Type is String)
      • flag_values: 0, 1 (Type is Int32)
      • long_name: Granule Pass Flag (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
      • valid_max: 1 (Type is Int32)
      • valid_min: 0 (Type is Int32)
  • gt1r(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
  • gt2r(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
  • gt1l(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
  • gt3l(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
  • gt2l(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
  • gt3r(Type is Group)
    • attributes
      • Description: Each group contains the quality assessment information for one Ground Track. (Type is String)
    • qa_perc_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of high-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of low-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_perc_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of medium-confidence signal photons for each surface type, based on the total number of photons for each surface type. (Type is String)
        • long_name: Percent_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_high[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of high-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_HIgh (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_perc_surf_type[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Float64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The percentage of geolocation segments for each surface type, based on the total number of geolocation segments. (Type is String)
        • long_name: Percent_Surface_Type (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: percent (Type is String)
    • qa_total_signal_conf_ph_low[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of low-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Low (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
    • qa_total_signal_conf_ph_med[ /quality_assessment/delta_time= 0..0] [ /ds_surf_type= 0..4] (Type is Int64)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: ../delta_time (Type is String)
        • description: The total number of medium-confidence signal photons for each surface type. (Type is String)
        • long_name: Total_Signal_Conf_Ph_Med (Type is String)
        • source: ATL03 ATBD, Section 8 (Type is String)
        • units: 1 (Type is String)
atlas_impulse_response(Type is Group)
  • attributes
    • Description: Contains parameters to characterize the ATLAS pulse energy and pulse shape, derived from the Start Pulse Detector data. These parameters are at the ICESat-2 geolocation segment rate (~20m along-track) (Type is String)
  • pce1_spot1(Type is Group)
    • attributes
      • Description: Contains parameters to characterize the ATLAS impulse response from the TEP photon histograms available for two of the three strong beams. (Type is String)
    • tep_histogram(Type is Group)
      • attributes
        • Description: Subgroup that contains the time of the histogram centers and the normalized histogram counts for each bin. (Type is String)
      Dimensions: [ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod = 0..0 ] [ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_hist_time = 0..1999 ]
      • tep_hist_time[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_hist_time= 0..1999] (Type is Float64)
        • attributes
          • description: The times associated with the TEP histogram bin centers, measured from the laser transmit time. (Type is String)
          • long_name: TEP Histogram Time (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: seconds (Type is String)
      • tep_tod[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod= 0..0] (Type is Float64)
        • attributes
          • description: The time of day at of the start of the data within the TEP histogram, in seconds since the ATLAS SDP GPS Epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: TEP Time Of Day (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • tep_duration[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod= 0..0] (Type is Float64)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The duration (or width) of data in the TEP histogram. Will generally be greater than 10 seconds. (Type is String)
          • long_name: TEP Duration (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: seconds (Type is String)
      • reference_tep_flag[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod= 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Flag that indicates the reference TEP has been used in place of a more recent TEP realization. 0=dynamic TEP used; 1=static reference TEP used. (Type is String)
          • flag_meanings: dynamic_tep_used, reference_tep_used (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Reference TEP Used (Type is String)
          • source: ATL03 ATBD, Section 7.2 (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • tep_hist_sum[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod= 0..0] (Type is Int64)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The total number of counts in the TEP histogram, after removing the background. (Type is String)
          • long_name: TEP Histogram Sum (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
      • tep_hist[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_hist_time= 0..1999] (Type is Float64)
        • attributes
          • coordinates: tep_hist_time (Type is String)
          • description: The normalized number of counts in each bin of the TEP histogram. (Type is String)
          • long_name: TEP Histogram (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
      • tep_bckgrd[ /atlas_impulse_response/pce1_spot1/tep_histogram/tep_tod= 0..0] (Type is Int32)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The average number of counts in the TEP histogram bins, after excluding bins that likely contain the transmit pulse. (Type is String)
          • long_name: TEP Background (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
  • pce2_spot3(Type is Group)
    • attributes
      • Description: Contains parameters to characterize the ATLAS impulse response from the TEP photon histograms available for two of the three strong beams. (Type is String)
    • tep_histogram(Type is Group)
      • attributes
        • Description: Subgroup that contains the time of the histogram centers and the normalized histogram counts for each bin. (Type is String)
      Dimensions: [ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod = 0..0 ] [ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_hist_time = 0..1999 ]
      • tep_hist_time[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_hist_time= 0..1999] (Type is Float64)
        • attributes
          • description: The times associated with the TEP histogram bin centers, measured from the laser transmit time. (Type is String)
          • long_name: TEP Histogram Time (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: seconds (Type is String)
      • tep_tod[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod= 0..0] (Type is Float64)
        • attributes
          • description: The time of day at of the start of the data within the TEP histogram, in seconds since the ATLAS SDP GPS Epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: TEP Time Of Day (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • tep_duration[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod= 0..0] (Type is Float64)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The duration (or width) of data in the TEP histogram. Will generally be greater than 10 seconds. (Type is String)
          • long_name: TEP Duration (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: seconds (Type is String)
      • reference_tep_flag[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod= 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Flag that indicates the reference TEP has been used in place of a more recent TEP realization. 0=dynamic TEP used; 1=static reference TEP used. (Type is String)
          • flag_meanings: dynamic_tep_used, reference_tep_used (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Reference TEP Used (Type is String)
          • source: ATL03 ATBD, Section 7.2 (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • tep_hist_sum[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod= 0..0] (Type is Int64)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The total number of counts in the TEP histogram, after removing the background. (Type is String)
          • long_name: TEP Histogram Sum (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
      • tep_hist[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_hist_time= 0..1999] (Type is Float64)
        • attributes
          • coordinates: tep_hist_time (Type is String)
          • description: The normalized number of counts in each bin of the TEP histogram. (Type is String)
          • long_name: TEP Histogram (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
      • tep_bckgrd[ /atlas_impulse_response/pce2_spot3/tep_histogram/tep_tod= 0..0] (Type is Int32)
        • attributes
          • coordinates: tep_tod (Type is String)
          • description: The average number of counts in the TEP histogram bins, after excluding bins that likely contain the transmit pulse. (Type is String)
          • long_name: TEP Background (Type is String)
          • source: ATL02 ATBD, Section 7.2 (Type is String)
          • units: counts (Type is String)
gt3l(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce1 (Type is String)
    • atlas_beam_type: weak (Type is String)
    • groundtrack_id: gt3l (Type is String)
    • atmosphere_profile: profile_3 (Type is String)
    • atlas_spot_number: 2 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt3l/bckgrd_atlas/delta_time = 0..84253 ]
    • delta_time[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt3l/bckgrd_atlas/delta_time= 0..84253] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt3l/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt3l/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt3l/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt3l/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt3l/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt3l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt3l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt3l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt3l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt3l/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt3l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3l/signal_find_output/land/delta_time = 0..4352 ]
      • delta_time[ /gt3l/signal_find_output/land/delta_time= 0..4352] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3l/signal_find_output/land/delta_time= 0..4352] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3l/signal_find_output/land/delta_time= 0..4352] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3l/signal_find_output/land/delta_time= 0..4352] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3l/signal_find_output/land/delta_time= 0..4352] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3l/signal_find_output/ocean/delta_time = 0..61871 ]
      • delta_time[ /gt3l/signal_find_output/ocean/delta_time= 0..61871] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3l/signal_find_output/ocean/delta_time= 0..61871] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3l/signal_find_output/ocean/delta_time= 0..61871] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3l/signal_find_output/ocean/delta_time= 0..61871] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3l/signal_find_output/ocean/delta_time= 0..61871] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3l/signal_find_output/sea_ice/delta_time = 0..62237 ]
      • delta_time[ /gt3l/signal_find_output/sea_ice/delta_time= 0..62237] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3l/signal_find_output/sea_ice/delta_time= 0..62237] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3l/signal_find_output/sea_ice/delta_time= 0..62237] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3l/signal_find_output/sea_ice/delta_time= 0..62237] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3l/signal_find_output/sea_ice/delta_time= 0..62237] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3l/signal_find_output/land_ice/delta_time = 0..10627 ]
      • delta_time[ /gt3l/signal_find_output/land_ice/delta_time= 0..10627] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3l/signal_find_output/land_ice/delta_time= 0..10627] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3l/signal_find_output/land_ice/delta_time= 0..10627] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3l/signal_find_output/land_ice/delta_time= 0..10627] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3l/signal_find_output/land_ice/delta_time= 0..10627] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3l/signal_find_output/inlandwater/delta_time = 0..4527 ]
      • delta_time[ /gt3l/signal_find_output/inlandwater/delta_time= 0..4527] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3l/signal_find_output/inlandwater/delta_time= 0..4527] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3l/signal_find_output/inlandwater/delta_time= 0..4527] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3l/signal_find_output/inlandwater/delta_time= 0..4527] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3l/signal_find_output/inlandwater/delta_time= 0..4527] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt3l/heights/delta_time = 0..2785147 ]
    • delta_time[ /gt3l/heights/delta_time= 0..2785147] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt3l/heights/delta_time= 0..2785147] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt3l/heights/delta_time= 0..2785147] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt3l/heights/delta_time= 0..2785147] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt3l/heights/delta_time= 0..2785147] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt3l/heights/delta_time= 0..2785147] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt3l/heights/delta_time= 0..2785147] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt3l/heights/delta_time= 0..2785147] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt3l/heights/delta_time= 0..2785147] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt3l/heights/delta_time= 0..2785147] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt3l/heights/delta_time= 0..2785147] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
gt2l(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce2 (Type is String)
    • atlas_beam_type: weak (Type is String)
    • groundtrack_id: gt2l (Type is String)
    • atmosphere_profile: profile_2 (Type is String)
    • atlas_spot_number: 4 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt2l/bckgrd_atlas/delta_time = 0..84260 ]
    • delta_time[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt2l/bckgrd_atlas/delta_time= 0..84260] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt2l/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt2l/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt2l/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt2l/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt2l/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt2l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt2l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt2l/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt2l/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt2l/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt2l/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2l/signal_find_output/ocean/delta_time = 0..61856 ]
      • delta_time[ /gt2l/signal_find_output/ocean/delta_time= 0..61856] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2l/signal_find_output/ocean/delta_time= 0..61856] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2l/signal_find_output/ocean/delta_time= 0..61856] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2l/signal_find_output/ocean/delta_time= 0..61856] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2l/signal_find_output/ocean/delta_time= 0..61856] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2l/signal_find_output/sea_ice/delta_time = 0..62228 ]
      • delta_time[ /gt2l/signal_find_output/sea_ice/delta_time= 0..62228] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2l/signal_find_output/sea_ice/delta_time= 0..62228] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2l/signal_find_output/sea_ice/delta_time= 0..62228] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2l/signal_find_output/sea_ice/delta_time= 0..62228] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2l/signal_find_output/sea_ice/delta_time= 0..62228] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2l/signal_find_output/land_ice/delta_time = 0..10335 ]
      • delta_time[ /gt2l/signal_find_output/land_ice/delta_time= 0..10335] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2l/signal_find_output/land_ice/delta_time= 0..10335] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2l/signal_find_output/land_ice/delta_time= 0..10335] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2l/signal_find_output/land_ice/delta_time= 0..10335] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2l/signal_find_output/land_ice/delta_time= 0..10335] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2l/signal_find_output/land/delta_time = 0..4225 ]
      • delta_time[ /gt2l/signal_find_output/land/delta_time= 0..4225] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2l/signal_find_output/land/delta_time= 0..4225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2l/signal_find_output/land/delta_time= 0..4225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2l/signal_find_output/land/delta_time= 0..4225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2l/signal_find_output/land/delta_time= 0..4225] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt2l/signal_find_output/inlandwater/delta_time = 0..4374 ]
      • delta_time[ /gt2l/signal_find_output/inlandwater/delta_time= 0..4374] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt2l/signal_find_output/inlandwater/delta_time= 0..4374] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt2l/signal_find_output/inlandwater/delta_time= 0..4374] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt2l/signal_find_output/inlandwater/delta_time= 0..4374] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt2l/signal_find_output/inlandwater/delta_time= 0..4374] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt2l/heights/delta_time = 0..2975195 ]
    • delta_time[ /gt2l/heights/delta_time= 0..2975195] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt2l/heights/delta_time= 0..2975195] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt2l/heights/delta_time= 0..2975195] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt2l/heights/delta_time= 0..2975195] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt2l/heights/delta_time= 0..2975195] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt2l/heights/delta_time= 0..2975195] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt2l/heights/delta_time= 0..2975195] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt2l/heights/delta_time= 0..2975195] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt2l/heights/delta_time= 0..2975195] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt2l/heights/delta_time= 0..2975195] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt2l/heights/delta_time= 0..2975195] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
ancillary_data(Type is Group)
  • attributes
    • Description: Contains information ancillary to the data product. This may include product characteristics, instrument characteristics and/or processing constants. (Type is String)
    • data_rate: Data within this group pertain to the granule in its entirety. (Type is String)
Dimensions: [ /ancillary_data/start_delta_time = 0..0 ]
  • start_delta_time[ /ancillary_data/start_delta_time= 0..0] (Type is Float64)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Number of GPS seconds since the ATLAS SDP epoch at the first data point in the file. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
      • long_name: ATLAS Start Time (Actual) (Type is String)
      • source: Derived (Type is String)
      • standard_name: time (Type is String)
      • units: seconds since 2018-01-01 (Type is String)
  • end_geoseg[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The ending geolocation segment number associated with the data contained within this granule. ICESat granule geographic regions are further refined by geolocation segments. During the geolocation process, a geolocation segment is created approximately every 20m from the start of the orbit to the end. The geolocation segments help align the ATLAS strong a weak beams and provide a common segment length for the L2 and higher products. The geolocation segment indices differ slightly from orbit-to-orbit because of the irregular shape of the Earth. The geolocation segment indices on ATL01 and ATL02 are only approximate because beams have not been aligned at the time of their creation. (Type is String)
      • long_name: Ending Geolocation Segment (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • version[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Version number of this granule within the release. It is a sequential number corresponding to the number of times the granule has been reprocessed for the current release. (Type is String)
      • long_name: Version (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
  • end_region[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The ending product-specific region number associated with the data contained within this granule. ICESat-2 data products are separated by geographic regions. The data contained within a specific region are the same for ATL01 and ATL02. ATL03 regions differ slightly because of different geolocation segment locations caused by the irregular shape of the Earth. The region indices for other products are completely independent. (Type is String)
      • long_name: Ending Region (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • atlas_sdp_gps_epoch[ 0..0] (Type is Float64)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS Standard Data Product (SDP) epoch (2018-01-01:T00.00.00.000000 UTC). Add this value to delta time parameters to compute full gps_seconds (relative to the GPS epoch) for each data point. (Type is String)
      • long_name: ATLAS Epoch Offset (Type is String)
      • source: Operations (Type is String)
      • units: seconds since 1980-01-06T00:00:00.000000Z (Type is String)
  • end_rgt[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The ending reference groundtrack (RGT) number associated with the data contained within this granule. There are 1387 reference groundtrack in the ICESat-2 repeat orbit. The reference groundtrack increments each time the spacecraft completes a full orbit of the Earth and resets to 1 each time the spacecraft completes a full cycle. (Type is String)
      • long_name: Ending Reference Groundtrack (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
      • valid_max: 1387 (Type is Int32)
      • valid_min: 1 (Type is Int32)
  • end_delta_time[ 0..0] (Type is Float64)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Number of GPS seconds since the ATLAS SDP epoch at the last data point in the file. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
      • long_name: ATLAS End Time (Actual) (Type is String)
      • source: Derived (Type is String)
      • standard_name: time (Type is String)
      • units: seconds since 2018-01-01 (Type is String)
  • end_orbit[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The ending orbit number associated with the data contained within this granule. The orbit number increments each time the spacecraft completes a full orbit of the Earth. (Type is String)
      • long_name: Ending Orbit Number (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • start_cycle[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The starting cycle number associated with the data contained within this granule. The cycle number is the counter of the number of 91-day repeat cycles completed by the mission. (Type is String)
      • long_name: Starting Cycle (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
      • valid_max: 99 (Type is Int32)
      • valid_min: 0 (Type is Int32)
  • data_end_utc[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: UTC (in CCSDS-A format) of the last data point within the granule. (Type is String)
      • long_name: End UTC Time of Granule (CCSDS-A, Actual) (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • control[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: PGE-specific control file used to generate this granule. To re-use, replace breaks (BR) with linefeeds. (Type is String)
      • long_name: Control File (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
  • start_gpssow[ 0..0] (Type is Float64)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: GPS seconds-of-week of the first data point in the granule. (Type is String)
      • long_name: Start GPS SOW of Granule (Actual) (Type is String)
      • source: Derived (Type is String)
      • units: seconds (Type is String)
  • granule_end_utc[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Requested end time (in UTC CCSDS-A) of this granule. (Type is String)
      • long_name: End UTC Time of Granule (CCSDS-A, Requested) (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • end_cycle[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The ending cycle number associated with the data contained within this granule. The cycle number is the counter of the number of 91-day repeat cycles completed by the mission. (Type is String)
      • long_name: Ending Cycle (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
      • valid_max: 99 (Type is Int32)
      • valid_min: 0 (Type is Int32)
  • granule_start_utc[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Requested start time (in UTC CCSDS-A) of this granule. (Type is String)
      • long_name: Start UTC Time of Granule (CCSDS-A, Requested) (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • release[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: Release number of the granule. The release number is incremented when the software or ancillary data used to create the granule has been changed. (Type is String)
      • long_name: Release Number (Type is String)
      • source: Operations (Type is String)
      • units: 1 (Type is String)
  • start_geoseg[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The starting geolocation segment number associated with the data contained within this granule. ICESat granule geographic regions are further refined by geolocation segments. During the geolocation process, a geolocation segment is created approximately every 20m from the start of the orbit to the end. The geolocation segments help align the ATLAS strong a weak beams and provide a common segment length for the L2 and higher products. The geolocation segment indices differ slightly from orbit-to-orbit because of the irregular shape of the Earth. The geolocation segment indices on ATL01 and ATL02 are only approximate because beams have not been aligned at the time of their creation. (Type is String)
      • long_name: Starting Geolocation Segment (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • start_orbit[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The starting orbit number associated with the data contained within this granule. The orbit number increments each time the spacecraft completes a full orbit of the Earth. (Type is String)
      • long_name: Starting Orbit Number (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • data_start_utc[ 0..0] (Type is String)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • source: Derived (Type is String)
      • description: UTC (in CCSDS-A format) of the first data point within the granule. (Type is String)
      • long_name: Start UTC Time of Granule (CCSDS-A, Actual) (Type is String)
      • units: 1 (Type is String)
  • end_gpsweek[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: GPS week number of the last data point in the granule. (Type is String)
      • long_name: Ending GPSWeek of Granule (Actual) (Type is String)
      • source: Derived (Type is String)
      • units: weeks from 1980-01-06 (Type is String)
  • start_rgt[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The starting reference groundtrack (RGT) number associated with the data contained within this granule. There are 1387 reference groundtrack in the ICESat-2 repeat orbit. The reference groundtrack increments each time the spacecraft completes a full orbit of the Earth and resets to 1 each time the spacecraft completes a full cycle. (Type is String)
      • long_name: Starting Reference Groundtrack (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
      • valid_max: 1387 (Type is Int32)
      • valid_min: 1 (Type is Int32)
  • end_gpssow[ 0..0] (Type is Float64)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: GPS seconds-of-week of the last data point in the granule. (Type is String)
      • long_name: Ending GPS SOW of Granule (Actual) (Type is String)
      • source: Derived (Type is String)
      • units: seconds (Type is String)
  • start_region[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: The starting product-specific region number associated with the data contained within this granule. ICESat-2 data products are separated by geographic regions. The data contained within a specific region are the same for ATL01 and ATL02. ATL03 regions differ slightly because of different geolocation segment locations caused by the irregular shape of the Earth. The region indices for other products are completely independent. (Type is String)
      • long_name: Starting Region (Type is String)
      • source: Derived (Type is String)
      • units: 1 (Type is String)
  • start_gpsweek[ 0..0] (Type is Int32)
    • attributes
      • contentType: auxiliaryInformation (Type is String)
      • description: GPS week number of the first data point in the granule. (Type is String)
      • long_name: Start GPSWeek of Granule (Actual) (Type is String)
      • source: Derived (Type is String)
      • units: weeks from 1980-01-06 (Type is String)
  • calibrations(Type is Group)
    • attributes
      • Description: This group contains calibrations derived from the ATLAS CAL products. (Type is String)
    Dimensions: [ /ancillary_data/calibrations/ds_channel = 0..19 ]
    • ds_channel[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int8)
      • attributes
        • description: Dimension scale for ATLAS PCE channels (1-16=strong, 17-20=weak) (Type is String)
        • long_name: Channel (Type is String)
        • units: 1 (Type is String)
        • valid_max: 20 (Type is Int8)
        • valid_min: 1 (Type is Int8)
        • contentType: referenceInformation (Type is String)
    • dead_time_radiometric_signal_loss(Type is Group)
      • attributes
        • Description: CAL34 - Dead-time Radiometric Signal Loss. Contains a table of radiometric corrections versus apparent return strength and width for several dead-time values. Correction is to be multiplied by raw return strength to get corrected return strength (Type is String)
      • cal34_product[ 0..5] (Type is String)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Name of ATLAS CAL Products containing the calibration data (Type is String)
          • long_name: CAL Product Name (Type is String)
          • source: CAL34 (Type is String)
          • units: 1 (Type is String)
      • gt1l(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
      • gt2l(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
      • gt1r(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
      • gt2r(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
      • gt3l(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
      • gt3r(Type is Group)
        • attributes
          • Description: CAL34 - Dead-time Radiometric Signal Loss. Provides a measure of counting efficiency loss as function of first photon bias for received photoelectron populations via combinations of return signal pulsewidth & mean photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
        • rad_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Radiometric Correction (width, strength, deadtime) (Type is String)
            • long_name: Radiometric Correction (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL34 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL34 (Type is String)
            • units: ns (Type is String)
    • first_photon_bias(Type is Group)
      • attributes
        • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
      • cal19_product[ 0..5] (Type is String)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Name of ATLAS CAL Products containing the calibration data (Type is String)
          • long_name: CAL Product Name (Type is String)
          • source: CAL19 (Type is String)
          • units: 1 (Type is String)
      • gt1l(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
      • gt2l(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
      • gt1r(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
      • gt2r(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
      • gt3l(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
      • gt3r(Type is Group)
        • attributes
          • Description: CAL19 -First Photon Bias. Provides a correction for first photon bias. (Type is String)
        • dead_time[ 0..5] (Type is Float32)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead time value (Type is String)
            • long_name: Dead Time (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
        • ffb_corr[ 0..5] [ 0..159] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: First Photon Bias Correction (width, strength, deadtime) in picoseconds. (Type is String)
            • long_name: FFB Correction (Type is String)
            • source: CAL19 (Type is String)
            • units: ps (Type is String)
        • strength[ 0..5] [ 0..159] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Spot strength in events/shot (strength, deadtime) (Type is String)
            • long_name: Beam Strength (Type is String)
            • source: CAL19 (Type is String)
            • units: 1 (Type is String)
        • width[ 0..5] [ 0..497] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Apparent width (width, deadtime) (Type is String)
            • long_name: Apparent Width (Type is String)
            • source: CAL19 (Type is String)
            • units: ns (Type is String)
    • low_link_impulse_response(Type is Group)
      • attributes
        • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
      Dimensions: [ /ancillary_data/calibrations/low_link_impulse_response/hist_x = 0..1999 ]
      • hist_x[ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Histogram bin x-values (Type is String)
          • long_name: Histogram Bin X Values (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
      • laser[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Laser Number (Type is String)
          • long_name: Laser (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
      • mode[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Laser Power Setting (Type is String)
          • long_name: Laser Power Setting (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
      • return_source[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • long_name: Return Source (Type is String)
          • description: Source of the events from which the data are derived. (Type is String)
          • flag_meanings: none tep maat echo (Type is String)
          • flag_values: 0, 1, 2, 3 (Type is Int32)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
          • valid_max: 3 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • cal20_product[ 0..0] (Type is String)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Name of ATLAS CAL Product containing the calibration data (Type is String)
          • long_name: CAL Product Name (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
      • num_bins[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Number of bins in the histogram (Type is String)
          • long_name: Number of Bins (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
      • temperature[ 0..0] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Temperature for which calibrations are provided. (Type is String)
          • long_name: Temperature (Type is String)
          • source: CAL20 (Type is String)
          • units: degreesC (Type is String)
      • bin_width[ 0..0] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Histogram bin width (Type is String)
          • long_name: Bin Width (Type is String)
          • source: CAL20 (Type is String)
          • units: seconds (Type is String)
      • side[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: A or B Side Component (Type is String)
          • flag_meanings: A B (Type is String)
          • flag_values: 1, 2 (Type is Int32)
          • long_name: A_or_B (Type is String)
          • source: CAL20 (Type is String)
          • units: 1 (Type is String)
          • valid_max: 2 (Type is Int32)
          • valid_min: 1 (Type is Int32)
      • gt1r(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
      • gt2r(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
      • gt1l(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
      • gt3l(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
      • gt2l(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
      • gt3r(Type is Group)
        • attributes
          • Description: CAL20 - System low link impulse response. Calibrates receiver impulse response, including optical and electrically introduced reflections. (Type is String)
        • hist[ /ancillary_data/calibrations/ds_channel= 0..19] [ /ancillary_data/calibrations/low_link_impulse_response/hist_x= 0..1999] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Per-Channel Histogram (Type is String)
            • long_name: Histogram (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
        • total_events[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Int64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Number of events used in constructing the per-channel histogram (Type is String)
            • long_name: Total Events (Type is String)
            • source: CAL20 (Type is String)
            • units: 1 (Type is String)
    • dead_time(Type is Group)
      • attributes
        • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
      • temperature[ 0..0] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Temperature for which calibrations are provided. (Type is String)
          • long_name: Temperature (Type is String)
          • source: CAL42 (Type is String)
          • units: degreesC (Type is String)
      • cal42_product[ 0..0] (Type is String)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Name of ATLAS CAL Product containing the calibration data (Type is String)
          • long_name: CAL Product Name (Type is String)
          • source: CAL42 (Type is String)
          • units: 1 (Type is String)
      • side[ 0..0] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: A or B side of the detector bank (Type is String)
          • flag_meanings: A B (Type is String)
          • flag_values: 1, 2 (Type is Int32)
          • long_name: Detector Bank Side (Type is String)
          • source: CAL42 (Type is String)
          • units: 1 (Type is String)
          • valid_max: 2 (Type is Int32)
          • valid_min: 1 (Type is Int32)
      • gt1r(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
      • gt2r(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
      • gt1l(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
      • gt3l(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
      • gt2l(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
      • gt3r(Type is Group)
        • attributes
          • Description: CAL42 - Dead-time. Estimates dead time for each ATLAS receiver channel accompanied by an estimated standard deviation for that measurement. photoelectrons/spot/shot, channel-to-channel basis. (Type is String)
        • dead_time[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Dead Time (channel) (Type is String)
            • long_name: DeadTime (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
        • sigma[ /ancillary_data/calibrations/ds_channel= 0..19] (Type is Float64)
          • attributes
            • contentType: auxiliaryInformation (Type is String)
            • description: Sigma (channel) (Type is String)
            • long_name: Sigma (Type is String)
            • source: CAL42 (Type is String)
            • units: seconds (Type is String)
  • atlas_engineering(Type is Group)
    • attributes
      • Description: This group contains statistics for ATLAS engineering data. (Type is String)
    Dimensions: [ /ancillary_data/atlas_engineering/ds_gt = 0..5 ] [ /ancillary_data/atlas_engineering/ds_stat = 0..3 ]
    • ds_gt[ /ancillary_data/atlas_engineering/ds_gt= 0..5] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Dimension scale for ATLAS Groundtracks (gt1l, gt1r, gt2l, gt2r, gt3l, gt3r) (Type is String)
        • flag_meanings: gt1l gt1r gt2l gt2r gt3l gt3r (Type is String)
        • flag_values: 1, 2, 3, 4, 5, 6 (Type is Int8)
        • long_name: GT Index (Type is String)
        • units: 1 (Type is String)
        • valid_max: 6 (Type is Int8)
        • valid_min: 1 (Type is Int8)
    • ds_stat[ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Dimension scale for statistics in the order mean, sdev, min, max (Type is String)
        • flag_meanings: mean sdev min max (Type is String)
        • flag_values: 1, 2, 3, 4 (Type is Int8)
        • long_name: Stat Index (Type is String)
        • units: 1 (Type is String)
        • valid_max: 5 (Type is Int8)
        • valid_min: 1 (Type is Int8)
    • spd_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Indicates if the active Start Pulse Detector (SPD) is side a (1) or side b (2). (Type is String)
        • flag_meanings: a b (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: SPD A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • det_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Indicates if the active detector (DET) is side A (1) or side B (2). (Type is String)
        • flag_meanings: a b (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: Detector Side, A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • lrs_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • flag_meanings: a b (Type is String)
        • description: Indicates if the active LRS is side A (1) or side B (2). (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: LRS Side A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • tams_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Indicates if the active TAMS is side a (1) or side b (2). (Type is String)
        • flag_meanings: a b (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: TAMS Side A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • laser_12_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • flag_meanings: 1 2 (Type is String)
        • description: Indicates if the active Laser is laser 1 or laser 2. (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: Laser 1 or Laser 2 (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • pdu_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • flag_meanings: a b (Type is String)
        • description: Indicates if the active PDU is side a (1) or side b (2). (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: PDU Side A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • ph_uncorrelated_error[ /ancillary_data/atlas_engineering/ds_gt= 0..5] [ /ancillary_data/start_delta_time= 0..0] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The estimate of uncorrelated height error. This is a six-valued array mapped onto gt1l, gt1r, gt2l, gt2r, gt3l, gt3r using the sc_orient parameter. (Type is String)
        • long_name: Uncorrelated Error (Type is String)
        • source: ATL03 ATBD, Section 7.7.2 (Type is String)
        • units: meters (Type is String)
    • hvpc_ab_flag[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • flag_meanings: a b (Type is String)
        • description: Indicates if the active High Voltage Power Converter (HVPC) is side A (1) or side B (2). (Type is String)
        • flag_values: 1, 2 (Type is Int32)
        • long_name: HVPC Side, A or B (Type is String)
        • source: Derived, L1B ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int32)
        • valid_min: 1 (Type is Int32)
    • transmit(Type is Group)
      • attributes
        • Description: This group contains transmit parameters. (Type is String)
      • tx_pulse_distribution[ /ancillary_data/atlas_engineering/ds_gt= 0..5] [ /ancillary_data/start_delta_time= 0..0] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The fraction of the transmit pulse energy in a given beam, based on pre-launch calibration. This is a six-valued array mapped onto gt1l, gt1r, gt2l, gt2r, gt3l, gt3r using the sc_orient parameter. (Type is String)
          • long_name: transmit pulse energy distribution (Type is String)
          • source: ATL03 ATBD, Section 7.2 (Type is String)
          • units: 1 (Type is String)
      • tx_pulse_skew_est[ /ancillary_data/start_delta_time= 0..0] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The difference between the means of the lower and upper threshold crossing times; a positive value corresponds to a positive skew in the pulse, and conversely for a negative value. (Type is String)
          • long_name: transmit pulse shape skew (Type is String)
          • source: ATL02, described in ATL03 ATBD Section 7.2.1 (Type is String)
          • units: seconds (Type is String)
      • tx_pulse_thresh_lower[ /ancillary_data/start_delta_time= 0..0] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The lower threshold setting of the start pulse detector. The threshold crossing times are used to determine the start pulse time, and estimate the start pulse shape. If this setting changes during a given granule, this parameter becomes two-valued. (Type is String)
          • long_name: transmit pulse lower threshold (Type is String)
          • source: ATL03 ATBD, Section 7.2 (Type is String)
          • units: volts (Type is String)
      • tx_pulse_thresh_upper[ /ancillary_data/start_delta_time= 0..0] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The upper threshold setting of the start pulse detector. The threshold crossing times are used to determine the start pulse time, and estimate the start pulse shape. If this setting changes during a given granule, this parameter becomes two-valued. (Type is String)
          • long_name: transmit pulse upper threshold (Type is String)
          • source: ATL03 ATBD, Section 7.2 (Type is String)
          • units: volts (Type is String)
      • tx_pulse_width_lower[ /ancillary_data/start_delta_time= 0..0] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The difference between the two crossing times of the transmit pulse (Type is String)
          • long_name: lower threshold crossing time difference (Type is String)
          • source: ATL02, described in ATL03 ATBD Section 7.2.1 (Type is String)
          • units: seconds (Type is String)
      • tx_pulse_width_upper[ /ancillary_data/start_delta_time= 0..0] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The difference between the two crossing times of the transmit pulse (Type is String)
          • long_name: upper threshold crossing time difference (Type is String)
          • source: ATL02, described in ATL03 ATBD Section 7.2.1 (Type is String)
          • units: seconds (Type is String)
      • tx_pulse_energy[ /ancillary_data/atlas_engineering/ds_gt= 0..5] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The mean, standard deviation, minimum and maximum values of the transmit energy for each beam as reported by the start pulse detector, averaged over a given ATL03 granule. This is a 6x4 array mapped onto gt1l, gt1r, gt2l, gt2r, gt3l, gt3r using the sc_orient parameter. (Type is String)
          • long_name: ATLAS Transmit Energy (Type is String)
          • source: ATL03 ATBD Section 7.2.1 (Type is String)
          • units: joules (Type is String)
    • receiver(Type is Group)
      • attributes
        • Description: This group contains receiver parameters. (Type is String)
      • rx_bckgrd_sensitivity[ /ancillary_data/atlas_engineering/ds_gt= 0..5] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Per-beam receiver background sensitivity. This is a six-valued array mapped onto gt1l, gt1r, gt2l, gt2r, gt3l, gt3r using the sc_orient parameter. (Type is String)
          • long_name: Receiver background sensivitiy (Type is String)
          • source: ATL02 ATBD, Sections 5.3.2 (Type is String)
          • units: events/joule (Type is String)
      • rx_return_sensitivity[ /ancillary_data/atlas_engineering/ds_gt= 0..5] [ /ancillary_data/atlas_engineering/ds_stat= 0..3] (Type is Float32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Per-beam receiver return sensitivity. This is a six-valued array mapped onto gt1l, gt1r, gt2l, gt2r, gt3l, gt3r using the sc_orient parameter. (Type is String)
          • long_name: Receiver return sensitivity (Type is String)
          • source: ATL02 ATBD, Sections 5.3.2 (Type is String)
          • units: events/joule (Type is String)
  • gt1r(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
  • gt2r(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
  • gt1l(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
  • altimetry(Type is Group)
    • attributes
      • Description: Constants used in altimetry processing. (Type is String)
    • atl03_pad[ 0..0] (Type is Float64)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Seconds of padding data needed for ATL03 processing. (Type is String)
        • long_name: Padding for ATL03 processing (Type is String)
        • source: Control (Type is String)
        • units: seconds (Type is String)
    • min_full_sat[ 0..1] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The minimum number of photons within a single transmit pulse that determines the pulse is fully saturated. (strong, weak) (Type is String)
        • long_name: Min Full Saturation Photons (Type is String)
        • source: Control (Type is String)
        • units: 1 (Type is String)
    • min_near_sat[ 0..1] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The minimum number of photons within a single transmit pulse that determines the pulse is nearly saturated. (strong, weak) (Type is String)
        • long_name: Min Near Saturation Photons (Type is String)
        • source: Control (Type is String)
        • units: 1 (Type is String)
    • min_sat_h[ 0..0] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The height, in meters, used for determining a saturated transmit pulse. (Type is String)
        • long_name: Minimum saturation height (Type is String)
        • source: Control (Type is String)
        • units: meters (Type is String)
    • podppd_pad[ 0..0] (Type is Float64)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • source: Control (Type is String)
        • description: Seconds of padding data needed for POD/PPD interpolation. (Type is String)
        • long_name: Padding for POD/PPD Interpolation (Type is String)
        • units: seconds (Type is String)
    • band_tol[ 0..0] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The tolerance, in meters, used to identify telemetry bands that do no intersect the DEM. (Type is String)
        • long_name: Tolerance for band-to-DEM comparison (Type is String)
        • source: Control (Type is String)
        • units: meters (Type is String)
  • gt3l(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
  • gt2l(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
  • tep(Type is Group)
    • attributes
      • Description: Contains information ancillary to the data product. This may include product characteristics, instrument characteristics and/or processing constants. (Type is String)
      • data_rate: Data within this group pertain to the granule in its entirety. (Type is String)
    Dimensions: [ /ancillary_data/tep/ds_gt = 0..5 ]
    • ds_gt[ /ancillary_data/tep/ds_gt= 0..5] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Dimension scale for ATLAS Groundtracks (gt1l, gt1r, gt2l, gt2r, gt3l, gt3r) (Type is String)
        • flag_meanings: gt1l gt1r gt2l gt2r gt3l gt3r (Type is String)
        • flag_values: 1, 2, 3, 4, 5, 6 (Type is Int8)
        • long_name: GT Index (Type is String)
        • units: 1 (Type is String)
        • valid_max: 6 (Type is Int8)
        • valid_min: 1 (Type is Int8)
    • tep_valid_spot[ 0..5] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: A 6x1 array indicating which TEP to use for each spot that does not have a TEP associated with it (e.g. which TEP to use to characterize spots 2, 4, 5, and 6). (Type is String)
        • flag_meanings: pce1_spot1 pce2_spot3 (Type is String)
        • flag_values: 1, 2 (Type is Int8)
        • long_name: Index of TEP Spot (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 2 (Type is Int8)
        • valid_min: 1 (Type is Int8)
    • tep_range_prim[ 0..1] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The range of time of flight of TEP photon events to include in generating a histogram or other analaysis of the primary TEP return (Type is String)
        • long_name: Range of Primary TEP Window (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: seconds (Type is String)
    • tep_start_x[ 0..0] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Value at the left edge of the first histogram bin. (Type is String)
        • long_name: TEP Start X (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • min_tep_secs[ 0..0] (Type is Float64)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Minimum seconds of data required for computing a TEP histogram. (Type is String)
        • long_name: Minimum TEP Seconds (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • tep_sec_window[ 0..1] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: The range of the secondary TEP window. Bins within this range are used in computing TEP rate. (Type is String)
        • long_name: TEP Secondary Window (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • tep_rm_noise[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Indicates if noise was removed from the TEP histogram. 0=background noise not removed; 1=background noise removed (Type is String)
        • flag_meanings: noise_not_removed noise_removed (Type is String)
        • flag_values: 0, 1 (Type is Int32)
        • long_name: Noise Removal Enabled (Type is String)
        • source: Ops (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int32)
        • valid_min: 0 (Type is Int32)
    • tep_bin_size[ 0..0] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Size of each TEP histogram bin. (Type is String)
        • long_name: TEP Bin Size (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • n_tep_bins[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Number of bins in each TEP histogram (Type is String)
        • long_name: Number of Bins (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • tep_normalize[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Indicates if the TEP histogram was normalized. 0=not normalized; 1=normalized (Type is String)
        • flag_meanings: not_normalized normalized (Type is String)
        • flag_values: 0, 1 (Type is Int32)
        • long_name: Normalization Enabled (Type is String)
        • source: Ops (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int32)
        • valid_min: 0 (Type is Int32)
    • min_tep_ph[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Minimum number of TEP photons required for computing a TEP histogram. (Type is String)
        • long_name: Minimum TEP photons (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • tep_peak_bins[ 0..0] (Type is Int32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Number of peak bins to remove for TEP background computation. (Type is String)
        • long_name: Number of Peak Bins to Remove (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • tep_gap_size[ 0..0] (Type is Float64)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • description: Minimum number of seconds separating each TEP histogram instance. (Type is String)
        • long_name: TEP Gap Size (Type is String)
        • source: Derived (Type is String)
        • units: seconds (Type is String)
    • tep_prim_window[ 0..1] (Type is Float32)
      • attributes
        • contentType: auxiliaryInformation (Type is String)
        • source: Derived (Type is String)
        • description: The range of the primary TEP window. Bins within this range are used in computing TEP rate. (Type is String)
        • long_name: TEP Primary Window (Type is String)
        • units: seconds (Type is String)
  • gt3r(Type is Group)
    • attributes
      • Description: Contains ancillary data used by the signal finding routine described in the ICESat-2 Global Geolocated Photons ATBD. (Type is String)
    • signal_find_input(Type is Group)
      • attributes
        • Description: Group contains the setup parameters for the signal finding algorithm. (Type is String)
        • data_rate: Parameters in this group are single-instances valid for the entire file. (Type is String)
      • sig_find_t_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time increment the algorithm uses to step through the photon cloud in a granule. Histograms are formed at each sig_find_t_inc interval to identify signal photon events. (Type is String)
          • long_name: Histogram time increment (Type is String)
          • source: ATL03, Section 5, _time (Type is String)
          • units: seconds (Type is String)
      • alpha_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Maximum slope allowed for slant histogram; if larger than this then don (Type is String)
          • long_name: Maximum Slope (Type is String)
          • source: ATL03, Section 5, _max (Type is String)
          • units: radians (Type is String)
      • delta_z_bg[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Width of a height bin in each atmospheric histogram, Ha, if calculating Ha from the photon cloud. Surface-type dependent. (Type is String)
          • long_name: Histogram height bin size for noise calculation from photon cloud (Type is String)
          • source: ATL03, Section 5, _zBG (Type is String)
      • e_linfit_edit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of linear fit to signal photons used to edit out noise during running linear fit edit of outliers. (Type is String)
          • long_name: Multiplier of STD of linear fit (Type is String)
          • source: ATL03, Section 5, e_linfit_edit (Type is String)
          • units: 1 (Type is String)
      • e_m[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of standard deviation of the number of background photon events per bin used in determining signal photon threshold. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of background (Type is String)
          • source: ATL03, Section 5, em (Type is String)
          • units: 1 (Type is String)
      • snrlow[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio below which all selected signal has low confidence. (Type is String)
          • long_name: Signal to noise ratio low (Type is String)
          • source: ATL03, Section 5, snrlow (Type is String)
          • units: 1 (Type is String)
      • nslw_v[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half the value of the height window used for slant histogramming relative to the surface used when varying the surface slope, alpha, to fill large gaps. Surface-type dependent. (Type is String)
          • long_name: Half height for variable slope slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw_v (Type is String)
          • units: meters (Type is String)
      • nphot_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The minimum number of photons over which to perform a linear fit to estimate the surface profile across a gap. Surface-type dependent. (Type is String)
          • long_name: Minimum number of photons to fill gap (Type is String)
          • source: ATL03, Section 5, Nphotmin (Type is String)
          • units: counts (Type is String)
      • delta_zmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height bin size for histogramming for first sweep. Surface-type dependent. (Type is String)
          • long_name: Minimum height bin size (Type is String)
          • source: ATL03, Section 5, _zmin (Type is String)
          • units: meters (Type is String)
      • delta_t_max[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Maximum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Maximum time (Type is String)
          • source: ATL03, Section 5, _tmax (Type is String)
      • lslant_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform slant histogramming for the strong beam. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: Flag to request slant histogramming for strong beams. (Type is String)
          • source: ATL03, Section 5, lslant (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • n_delta_z2[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmax1 and delta_zmax2. Surface-type dependent. (Type is String)
          • long_name: number of increments in z2 (Type is String)
          • source: ATL03, Section 5, n_z2 (Type is String)
          • units: counts (Type is String)
      • e_m_mult[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of e_m used to determine Thsig2, threshold for singular bins. Surface-type dependent. (Type is String)
          • long_name: Multiplier of STD of e_m (Type is String)
          • source: ATL03, Section 5, em_mult (Type is String)
          • units: 1 (Type is String)
      • delta_t_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: seconds (Type is String)
          • description: Minimum time interval over which photons are selected to histogram. Surface-type dependent. (Type is String)
          • long_name: Histogram Minimum time (Type is String)
          • source: ATL03, Section 5, _tmin (Type is String)
      • r2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of (maximum number of photons in any one bin of contiguous signal bins)/(Maximum number of photons in largest bin) in order to accept a group of potential signal bins as signal. Surface-type dependent. (Type is String)
          • long_name: Minimum ratio2 (Type is String)
          • source: ATL03, Section 5, R2 (Type is String)
          • units: 1 (Type is String)
      • snrmed[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Signal to noise ratio above which all selected signal has high confidence. Selected signal with signal to noise ratio between snrlow and snrmed is marked as medium confidence. (Type is String)
          • long_name: Signal to noise ratio medium (Type is String)
          • source: ATL03, Section 5, snrmed (Type is String)
          • units: 1 (Type is String)
      • n_delta_z1[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The number of increments between delta_zmin and delat_zmax1. Surface-type dependent. (Type is String)
          • long_name: number of increments in z1 (Type is String)
          • source: ATL03, Section 5, n_z1 (Type is String)
          • units: counts (Type is String)
      • min_fit_time_fact[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: The factor to multiply DTIME by to obtain the minimum time over which to fit a line to a height profile to calculate the local slope using running linear fits, min_fit_time. (Type is String)
          • long_name: minimum fit time factor (Type is String)
          • source: ATL03, Section 5, min_fit_time_fact (Type is String)
          • units: seconds (Type is String)
      • pc_bckgrd_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then always use the photon cloud to calculate the background photon rate, if false only use the photon cloud in the absence of the atmospheric histogram. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: calculated background rate flag (Type is String)
          • source: ATL03, Section 5, Lpcbg (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • t_gap_big[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: For time gaps less than this value, slant histogramming is performed relative to the linear slope calculated from the surrounding signal. For time gaps greater than or equal to this value the slope is varied when performing slant histogramming. Surface-type dependent. (Type is String)
          • long_name: Gap size criteria (Type is String)
          • source: ATL03, Section 5, tgapbig (Type is String)
          • units: seconds (Type is String)
      • e_a[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of Ha_sigma used to determine which bins in the atmospheric histogram may contain signal photon events. Surface-type dependent. (Type is String)
          • long_name: Multiplier of Ha_sigma (Type is String)
          • source: ATL03, Section 5, ea (Type is String)
          • units: 1 (Type is String)
      • delta_zmax2[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • units: meters (Type is String)
          • description: Maximum height bin size for histogramming for second sweep. Surface-type dependent. (Type is String)
          • long_name: Maximum height bin size 2 (Type is String)
          • source: ATL03, Section 5, _zmax2 (Type is String)
      • nslw[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Half of the value of the height window used for slant histogramming relative to the surface defined by the linear fit to the surrounding photons at slope, alpha. Surface-type dependent. (Type is String)
          • long_name: half height for slant histogramming (Type is String)
          • source: ATL03, Section 5, nslw (Type is String)
          • units: meters (Type is String)
      • e_linfit_slant[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Multiplier of sigma_linfit, the standard deviation of the residuals between the actual photon events used to estimate the surface using a linear fit; all photons with height > e_linfit_slant (Type is String)
          • long_name: Multiplier of sigma linfit (Type is String)
          • source: ATL03, Section 5, e_linfit_slant (Type is String)
          • units: 1 (Type is String)
      • addpad_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) that if true (=1) then identify additional photon events as padding to achieve htspanin for each time interval sig_find_t_inc. (Type is String)
          • long_name: Additional photon flag (Type is String)
          • source: ATL03, Section 5, Addpad (Type is String)
          • units: 1 (Type is String)
      • nbin_min[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum number of bins in a histogram required for the algorithm to be able to process the histogram. (Type is String)
          • long_name: Minimum number of bins (Type is String)
          • source: ATL03, Section 5, Nbinmin (Type is String)
          • units: counts (Type is String)
      • htspanmin[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum height span for each time interval of photons with confidence flag > 0. If the height span is < htspanmin then all photons not previously selected within +/- htspanmin/2 of the median height of the signal photons selected are marked with a confidence flag of 1. Surface-type dependent. (Type is String)
          • long_name: Minimum height span (Type is String)
          • source: ATL03, Section 5, Htspanmin (Type is String)
          • units: meters (Type is String)
      • alpha_inc[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Increment by which the slope is varied for slant histogramming over large gaps (Type is String)
          • long_name: Slope Increment (Type is String)
          • source: ATL03, Section 5, _inc (Type is String)
          • units: radians (Type is String)
      • out_edit_flag[ 0..4] (Type is Int32)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Binary (logical) flag, if true (=1) then perform an n _ edit on a running linear fit to identified signal to remove outliers. Surface-type dependent. (Type is String)
          • flag_meanings: false true (Type is String)
          • flag_values: 0, 1 (Type is Int32)
          • long_name: outlier edit flag (Type is String)
          • source: ATL03, Section 5, Ledit (Type is String)
          • units: 1 (Type is String)
          • valid_max: 1 (Type is Int32)
          • valid_min: 0 (Type is Int32)
      • delta_t_gap_min[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum size of a time gap in the height profile over which to use variable slope slant histogramming. (Type is String)
          • long_name: Mimimum delta time gap (Type is String)
          • source: ATL03, Section 5, _time_gapmin (Type is String)
          • units: seconds (Type is String)
      • delta_t_lin_fit[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Time span over which to perform a running linear fit to identified signal photon events when editing outliers. Surface type dependent. (Type is String)
          • long_name: Linear fit time increment (Type is String)
          • source: ATL03, Section 5, _t_linfit_edit (Type is String)
          • units: seconds (Type is String)
      • r[ 0..4] (Type is Float64)
        • attributes
          • contentType: auxiliaryInformation (Type is String)
          • description: Minimum ratio of max number of photons in histogram bin to mean noise value that must exist to consider a bin a signal bin. (Type is String)
          • long_name: Minimum ratio (Type is String)
          • source: ATL03, Section 5, R (Type is String)
          • units: 1 (Type is String)
gt3r(Type is Group)
  • attributes
    • Description: Each group contains the segments for one Ground Track. As ICESat-2 orbits the earth, sequential transmit pulses illuminate six ground tracks on the surface of the earth. The track width is approximately 14m. Each ground track is numbered, according to the laser spot number that generates a given ground track. Ground tracks are numbered from the left to the right in the direction of spacecraft travel as: 1L, 1R in the left-most pair of beams; 2L, 2R for the center pair of beams; and 3L, 3R for the right-most pair of beams. (Type is String)
    • atlas_pce: pce1 (Type is String)
    • atlas_beam_type: strong (Type is String)
    • groundtrack_id: gt3r (Type is String)
    • atmosphere_profile: profile_3 (Type is String)
    • atlas_spot_number: 1 (Type is String)
    • sc_orientation: Forward (Type is String)
  • bckgrd_atlas(Type is Group)
    • attributes
      • Description: Contains data related to the 50-shot background count, including telemetry and range windows. (Type is String)
    Dimensions: [ /gt3r/bckgrd_atlas/delta_time = 0..91170 ]
    • delta_time[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float64)
      • attributes
        • description: Elapsed GPS Seconds from the ATLAS SDP GPS Epoch, referenced to the start of the 50-shot sum. This is based on every fiftieth laser fire time, which leads to a very close alignment with major frame boundaries (+/- 1 shot). The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Time at the start of ATLAS 50-shot sum (Type is String)
        • source: ATL02 (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • tlm_height_band1[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • long_name: Height of the telemetry band 1 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
        • description: The height in meters of the telemetry band 1. (Type is String)
    • bckgrd_rate[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The background count rate from the 50-shot altimetric histogram after removing the number of likely signal photons based on Section 5. (Type is String)
        • long_name: Background count rate based on the ATLAS 50-shot sum (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts / second (Type is String)
    • tlm_top_band1[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 1, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 1. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • tlm_top_band2[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The ellipsoidal heights with respect to WGS-84 of the top of the telemetry band 2, with all geophysical corrections applied. (Type is String)
        • long_name: Ellipsoidal height of the top of the telemetry band 2. (Type is String)
        • source: ATL03 ATBD, Section 3.2, 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height_reduced[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window after subtracting the height span of the signal photon events in the 50-shot span. (Type is String)
        • long_name: Altimetric range window height - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_hist_top[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the top of the altimetric histogram, in meters above the WGS-84 ellipsoid, with all geophysical corrections applied. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Top of the altimetric range window (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • bckgrd_counts_reduced[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Number of photon counts in the 50-shot sum after subtracting the number of signal photon events, defined as in ATBD Section 5, in that span. (Type is String)
        • long_name: ATLAS 50-shot background count - reduced (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
    • tlm_height_band2[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: The height in meters of the telemetry band 2. (if 0, second band is not present). (Type is String)
        • long_name: Height of the telemetry band 2 (Type is String)
        • source: ATL03 ATBD, Section 7.3.2 (Type is String)
        • units: meters (Type is String)
    • bckgrd_int_height[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Float32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: The height of the altimetric range window. This is the height over which the 50-shot sum is generated. Parameter is ingested at 50-Hz, and values are repeated to form a 200-Hz array. (Type is String)
        • long_name: Altimetric range window width (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: meters (Type is String)
    • pce_mframe_cnt[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Int64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Major Frame ID - The major frame ID is read from the DFC and starts counting at DFC POR. The counter is used to identify individual major frames across diag and science packets. This counter can go for about 2.7 years before rolling over. It is in the first time tag science packet. Used as part of the photon ID and the safest way to align data within different APIDs or at different rates. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: ATL02 (Type is String)
        • units: counts (Type is String)
    • bckgrd_counts[ /gt3r/bckgrd_atlas/delta_time= 0..91170] (Type is Int32)
      • attributes
        • contentType: modelResult (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Onboard 50 shot background (200 Hz) sum of photon events within the altimetric range window. (Type is String)
        • long_name: ATLAS 50-shot background count (Type is String)
        • source: ATL03 ATBD Section 7.3 (Type is String)
        • units: counts (Type is String)
  • geolocation(Type is Group)
    • attributes
      • Description: Contains parameters related to geolocation. The rate of all of these parameters is at the rate corresponding to the ICESat-2 Geolocation Along Track Segment interval (nominally 20 m along-track). In the case of no photons within the segment (segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: Data within this group are stored at the ICESat-2 20m segment rate. (Type is String)
    Dimensions: [ /gt3r/geolocation/delta_time = 0..163492 ]
    • reference_photon_lat[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Latitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Latitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • delta_time[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: reference_photon_lat, reference_photon_lon (Type is String)
        • description: Transmit time of the reference photon, measured in seconds from the atlas_sdp_gps_epoch. If there is no reference photon, this time corresponds to the approximate mid-point time associated with the along-track geolocation segment edge. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Delta Time (Type is String)
        • source: Derived (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • range_bias_corr[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The range_bias estimated from geolocation analysis. (Type is String)
        • long_name: range bias correction (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: meters (Type is String)
    • neutat_delay_derivative[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Change in neutral atmospheric delay per height change (Type is String)
        • long_name: (Neutral Atmosphere delay)/dh (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters/meters (Type is String)
    • reference_photon_lon[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time (Type is String)
        • description: Longitude of each reference photon. Computed from the ECF Cartesian coordinates of the bounce point. In the case of no photons within the segment (segment_ph_cnt=0), the coordinates are the midpoint of the geolocation segment on the reference ground track. (Type is String)
        • long_name: Segment Longitude (Type is String)
        • source: ATL03G ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • sigma_across[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated Cartesian across-track uncertainity (1-sigma) for the refrerence photon (Type is String)
        • long_name: across-track geolocation uncertainty (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • sigma_lon[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic east Longitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: longitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: degrees (Type is String)
    • ref_azimuth[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Azimuth of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from North and positive towards East. (Type is String)
        • long_name: Azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: azimuth (Type is String)
        • units: radians (Type is String)
    • ref_elev[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Elevation of the unit pointing vector for the reference photon in the local ENU frame in radians. The angle is measured from East-North plane and positive towards Up (Type is String)
        • long_name: elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • standard_name: elevation (Type is String)
        • units: radians (Type is String)
    • neutat_ht[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Reference height of the neutral atmosphere range correction (Type is String)
        • long_name: Neutral atmosphere ref height (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
    • ph_index_beg[ /gt3r/geolocation/delta_time= 0..163492] (Type is Int64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index (1-based) within the photon-rate data of the first photon within this segment. Use in conjunction with segment_ph_cnt. (Type is String)
        • long_name: Photon Index Begin (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
        • _FillValue: 0 (Type is Int64)
    • solar_azimuth[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The azimuth of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from North and is positive towards East. ATL03g provides this value in radians; it is converted to degrees for ATL03 output. (Type is String)
        • long_name: solar azimuth (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees_east (Type is String)
    • surf_type[ /gt3r/geolocation/delta_time= 0..163492] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Flags describing which surface types this interval is associated with. 0=not type, 1=is type. Order of array is land, ocean, sea ice, land ice, inland water. (Type is String)
        • flag_meanings: not_type is_type (Type is String)
        • flag_values: 0, 1 (Type is Int8)
        • long_name: Surface Type (Type is String)
        • source: ATL03 ATBD, Section 4 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • sigma_lat[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated geodetic Latitude uncertainty (1-sigma), for the reference photon bounce point. (Type is String)
        • long_name: latitude uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • tx_pulse_width_lower[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the lower threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Lower Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_along[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated cartesian along-track uncertainanty (1-sigma) for the reference photon (Type is String)
        • long_name: along-track geolocation uncertainity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters (Type is String)
    • tx_pulse_skew_est[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the averages of the lower and upper threshold crossing times. This is an estimate of the transmit pulse skew. (Type is String)
        • long_name: Transmit Pulse Skew Estimate (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • tx_pulse_energy[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average transmit pulse energy, measured by the internal laser energy monitor, split into per-beam measurements. (Type is String)
        • long_name: Transmit Pulse Energy (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: Joules (Type is String)
    • tx_pulse_width_upper[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The average distance between the upper threshold crossing times measured by the Start Pulse Detector. (Type is String)
        • long_name: Transmit Pulse Energy Upper Width (Type is String)
        • source: ATL02 ATBD, Section 7.2 (Type is String)
        • units: seconds (Type is String)
    • sigma_h[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Estimated height uncertainty (1-sigma) for the reference photon bounce point. (Type is String)
        • long_name: height uncertainty (Type is String)
        • source: ATL03G ATBD, Section 3.6 (Type is String)
        • units: 1 (Type is String)
    • podppd_flag[ /gt3r/geolocation/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 0 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Composite POD/PPD flag that indicates the quality of input geolocation products for the specific ATL03 segment. A non-zero value may indicate that geolocation solutions are degraded. The ATL03 sigma values should indicate the degree of uncertainty associated with the degradation. Possible values are: 0=NOMINAL; 1=POD_DEGRADE; 2=PPD_DEGRADE; 3=PODPPD_DEGRADE. (Type is String)
        • flag_meanings: nominal pod_degrade ppd_degrade podppd_degrade (Type is String)
        • flag_values: 0, 1, 2, 3 (Type is Int8)
        • long_name: POD_PPD Flag (Type is String)
        • source: ANC04, ANC05 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 3 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • velocity_sc[ /gt3r/geolocation/delta_time= 0..163492] [ /ds_xyz= 0..2] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Spacecraft velocity components (east component, north component, up component) an observer on the ground would measure. While values are common to all beams, this parameter is naturally produced as part of geolocation. (Type is String)
        • long_name: spacecraft velocity (Type is String)
        • source: ATL03G ATBD (Type is String)
        • units: meters/second (Type is String)
    • full_sat_fract[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be fully saturated. (Type is String)
        • long_name: Full Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_id[ /gt3r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: A 7 digit number identifiying the along-track geolocation segment number. These are sequential, starting with 1 for the first segment after an ascending equatorial crossing node. (Type is String)
        • long_name: along-track segment ID number. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: 1 (Type is String)
    • near_sat_fract[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The fraction of pulses within the segment determined to be nearly saturated. (Type is String)
        • long_name: Near Saturation Fraction (Type is String)
        • source: ATL03 ATBD (Type is String)
        • units: 1 (Type is String)
        • valid_max: 1. (Type is Float32)
        • valid_min: 0. (Type is Float32)
    • segment_ph_cnt[ /gt3r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Number of photons in a given along-track segment. In the case of no photons within the segment (segment_ph_cnt=0), most other parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
        • long_name: Number of photons (Type is String)
        • source: Derived (Type is String)
        • units: counts (Type is String)
    • solar_elevation[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The elevation of the sun position vector from the reference photon bounce point position in the local ENU frame. The angle is measured from the East-North plane and is positive Up. ATL03g provides this value in radians; it is converted to degress for ATL03 output. (Type is String)
        • long_name: solar elevation (Type is String)
        • source: ATL03G ATBD, Section 3.3 (Type is String)
        • units: degrees (Type is String)
    • bounce_time_offset[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The difference between the transmit time and the ground bounce time of the reference photons. (Type is String)
        • long_name: ground bounce time offset (Type is String)
        • source: ATL03 ATBD, Section 3.3 (Type is String)
        • units: seconds (Type is String)
    • segment_length[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: The along-track length of the along-track segment. Nominally these are 20m, but they vary from 19.8m to 20.2m. (Type is String)
        • long_name: along-track segment length (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • reference_photon_index[ /gt3r/geolocation/delta_time= 0..163492] (Type is Int32)
      • attributes
        • _FillValue: 0 (Type is Int32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Index of the reference photon within the set of photons grouped within in segment. To recover the position of the reference photon within the photon-rate arrays, add ref_ph_ndx to the corresponding ph_ndx_beg and subtract 1. If no reference photon was selected, this value will indicate that the reference photon defaulted to the first photon. In the case of no photons within the segment (segment_ph_cnt=0), the value should be 0. (Type is String)
        • long_name: Reference Photon Index (Type is String)
        • source: ATL03 ATBD, Section 3.2 (Type is String)
        • units: counts (Type is String)
    • altitude_sc[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • _FillValue: 1.7976931348623157e+308 (Type is Float64)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Height of the spacecraft above the WGS84 ellipsoid. (Type is String)
        • long_name: Altitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • units: meters (Type is String)
    • segment_dist_x[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float64)
      • attributes
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Along-track distance from the equator crossing to the start of the 20 meter geolocation segment. (Type is String)
        • long_name: Segment Distance from EQC (Type is String)
        • source: Derived (Type is String)
        • units: meters (Type is String)
    • neutat_delay_total[ /gt3r/geolocation/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time reference_photon_lat reference_photon_lon (Type is String)
        • description: Total neutral atmosphere delay correction (wet+dry). (Type is String)
        • long_name: Total Neutral Atmospheric Delay (Type is String)
        • source: ATL03a ATBD (Type is String)
        • units: meters (Type is String)
  • geophys_corr(Type is Group)
    • attributes
      • Description: Contains parameters used to correct photon heights for selected geophysical effects. Additional geophysical parameters (dac and tide_ocean) are not applied and provided for informational purposes only. All parameters are posted at the same interval as the ICESat-2 Geolocation Along-Track Segment interval (nominally 20m along-track). In the case of no photons within the segment (../geolocation/segment_ph_cnt=0), most parameters are filled with invalid or best-estimate values. Maintaining geolocation segments with no photons allows for the geolocation segment arrays to be directly aligned across the gtx groups. (Type is String)
      • data_rate: These parameters are stored at the ICESat-2 Geolocation Along Track Segment rate (nominally every 20 m along-track). (Type is String)
    Dimensions: [ /gt3r/geophys_corr/delta_time = 0..163492 ]
    • delta_time[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • description: Elapsed seconds from the ATLAS SDP GPS Epoch, corresponding to the transmit time of the reference photon. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • dem_flag[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Int8)
      • attributes
        • _FillValue: 127 (Type is Int8)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Indicates source of the DEM height. Values: 0=None, 1=Arctic, 2=GMTED, 3=MSS, 4=Antarctic. (Type is String)
        • flag_meanings: none arctic gmted mss antarctic (Type is String)
        • flag_values: 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: dem source flag (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: 0 (Type is Int8)
    • tide_ocean[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Ocean Tides including diurnal and semi-diurnal (harmonic analysis), and longer period tides (dynamic and self-consistent equilibrium). This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Ocean Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • tide_earth[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Tides (Type is String)
        • long_name: Earth Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.3 (Type is String)
        • units: meters (Type is String)
    • dac[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Dynamic Atmospheric Correction (DAC) includes inverted barometer (IB) effect. This correction is not applied to the photon heights and provided only as supplemental information. (Type is String)
        • long_name: Dynamic Atmosphere Correction (Type is String)
        • source: ATL03 ATBD, Section 6.3.2 (Type is String)
        • units: meters (Type is String)
    • tide_load[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Load Tide - Local displacement due to Ocean Loading (-6 to 0 cm). (Type is String)
        • long_name: Load Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.4 (Type is String)
        • units: meters (Type is String)
    • dem_h[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Best available DEM (in priority of Arctic/Antarctic/GMTED/MSS) value at the location of the reference photon. (Type is String)
        • long_name: DEM Height (Type is String)
        • source: ATL03 ATBD Section 6.3 (Type is String)
        • units: meters (Type is String)
    • tide_equilibrium[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time (Type is String)
        • description: Long period equilibrium tide self-consistent with ocean tide model (+-0.04m). This correction is not applied to the photon heights and is provided only as a supplemental information. (Type is String)
        • long_name: Long Period Equilibrium Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.1 (Type is String)
        • units: meters (Type is String)
    • geoid[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Geoid height above WGS-84 reference ellipsoid (range -107 to 86m). Not applied on the product; requested by higher-level products. (Type is String)
        • long_name: Geoid (Type is String)
        • source: ATL03 ATBD, Section 6.3.8 (Type is String)
        • units: meters (Type is String)
    • tide_oc_pole[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • description: Surface deformation of the Earth due to loading from the centrifugal effect of polar motion upon the oceans (-2 to 2 mm). (Type is String)
        • long_name: Ocean Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.6 (Type is String)
        • units: meters (Type is String)
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
    • tide_pole[ /gt3r/geophys_corr/delta_time= 0..163492] (Type is Float32)
      • attributes
        • _FillValue: 3.402823466e+38 (Type is Float32)
        • coordinates: delta_time (Type is String)
        • description: Solid Earth Pole Tide -Rotational deformation due to polar motion (-1.5 to 1.5 cm). (Type is String)
        • long_name: Solid Earth Pole Tide (Type is String)
        • source: ATL03 ATBD, Section 6.3.5 (Type is String)
        • units: meters (Type is String)
  • signal_find_output(Type is Group)
    • attributes
      • Description: Parameters output for each time interval for which signal photons were selected, and the confidence flag set, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      • data_rate: Data are stored at the rate of signal finding time intervals. (Type is String)
    • ocean(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3r/signal_find_output/ocean/delta_time = 0..72590 ]
      • delta_time[ /gt3r/signal_find_output/ocean/delta_time= 0..72590] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3r/signal_find_output/ocean/delta_time= 0..72590] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3r/signal_find_output/ocean/delta_time= 0..72590] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3r/signal_find_output/ocean/delta_time= 0..72590] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3r/signal_find_output/ocean/delta_time= 0..72590] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • sea_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3r/signal_find_output/sea_ice/delta_time = 0..62236 ]
      • delta_time[ /gt3r/signal_find_output/sea_ice/delta_time= 0..62236] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3r/signal_find_output/sea_ice/delta_time= 0..62236] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3r/signal_find_output/sea_ice/delta_time= 0..62236] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3r/signal_find_output/sea_ice/delta_time= 0..62236] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3r/signal_find_output/sea_ice/delta_time= 0..62236] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land_ice(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3r/signal_find_output/land_ice/delta_time = 0..19643 ]
      • delta_time[ /gt3r/signal_find_output/land_ice/delta_time= 0..19643] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3r/signal_find_output/land_ice/delta_time= 0..19643] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3r/signal_find_output/land_ice/delta_time= 0..19643] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3r/signal_find_output/land_ice/delta_time= 0..19643] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3r/signal_find_output/land_ice/delta_time= 0..19643] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • land(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3r/signal_find_output/land/delta_time = 0..5539 ]
      • delta_time[ /gt3r/signal_find_output/land/delta_time= 0..5539] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3r/signal_find_output/land/delta_time= 0..5539] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3r/signal_find_output/land/delta_time= 0..5539] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3r/signal_find_output/land/delta_time= 0..5539] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3r/signal_find_output/land/delta_time= 0..5539] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
    • inlandwater(Type is Group)
      • attributes
        • Description: Surface-type specific parameters output for each time interval for which signal photons were selected, based on the algorithm in Section 5. Histogram parameters are from the histogram that was used to identify signal photons and set the confidence parameter for a given time increment. (Type is String)
      Dimensions: [ /gt3r/signal_find_output/inlandwater/delta_time = 0..17734 ]
      • delta_time[ /gt3r/signal_find_output/inlandwater/delta_time= 0..17734] (Type is Float64)
        • attributes
          • contentType: physicalMeasurement (Type is String)
          • description: Number of GPS seconds since the ATLAS SDP epoch. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
          • long_name: Elapsed GPS seconds (Type is String)
          • source: Derived via Time Tagging (Type is String)
          • standard_name: time (Type is String)
          • units: seconds since 2018-01-01 (Type is String)
      • bckgrd_sigma[ /gt3r/signal_find_output/inlandwater/delta_time= 0..17734] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The standard deviation of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin sigma (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • t_pc_delta[ /gt3r/signal_find_output/inlandwater/delta_time= 0..17734] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The histogram bin width (integration time) along-track used to find signal photons. (Type is String)
          • long_name: bin width size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: seconds (Type is String)
      • bckgrd_mean[ /gt3r/signal_find_output/inlandwater/delta_time= 0..17734] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: The mean of the number of background counts expected in one height bin of the histogram of width dzATM over time period, dtATM (Type is String)
          • long_name: background counts per bin (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: counts (Type is String)
      • z_pc_delta[ /gt3r/signal_find_output/inlandwater/delta_time= 0..17734] (Type is Float32)
        • attributes
          • _FillValue: 3.402823466e+38 (Type is Float32)
          • coordinates: delta_time (Type is String)
          • description: Height bin size of the histogram used to find signal photons. (Type is String)
          • long_name: bin height size (Type is String)
          • source: ATL03 ATBD, Section 5 (Type is String)
          • units: meters (Type is String)
  • heights(Type is Group)
    • attributes
      • Description: Contains arrays of the parameters for each received photon. (Type is String)
      • data_rate: Data are stored at the photon detection rate. (Type is String)
    Dimensions: [ /gt3r/heights/delta_time = 0..4548381 ]
    • delta_time[ /gt3r/heights/delta_time= 0..4548381] (Type is Float64)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: lat_ph lon_ph (Type is String)
        • description: The transmit time of a given photon, measured in seconds from the ATLAS Standard Data Product Epoch. Note that multiple received photons associated with a single transmit pulse will have the same delta_time. The ATLAS Standard Data Products (SDP) epoch offset is defined within /ancillary_data/atlas_sdp_gps_epoch as the number of GPS seconds between the GPS epoch (1980-01-06T00:00:00.000000Z UTC) and the ATLAS SDP epoch. By adding the offset contained within atlas_sdp_gps_epoch to delta time parameters, the time in gps_seconds relative to the GPS epoch can be computed. (Type is String)
        • long_name: Elapsed GPS seconds (Type is String)
        • source: Operations (Type is String)
        • standard_name: time (Type is String)
        • units: seconds since 2018-01-01 (Type is String)
    • lat_ph[ /gt3r/heights/delta_time= 0..4548381] (Type is Float64)
      • attributes
        • coordinates: delta_time lon_ph (Type is String)
        • description: Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Latitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: latitude (Type is String)
        • units: degrees_north (Type is String)
        • valid_max: 90. (Type is Float64)
        • valid_min: -90. (Type is Float64)
    • dist_ph_along[ /gt3r/heights/delta_time= 0..4548381] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Along-track distance in a segment projected to the ellipsoid of the received photon, based on the Along-Track Segment algorithm. Total along track distance can be found by adding this value to the sum of segment lengths measured from the start of the most recent reference groundtrack. (Type is String)
        • long_name: Distance from equator crossing. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
    • signal_conf_ph[ /gt3r/heights/delta_time= 0..4548381] [ /ds_surf_type= 0..4] (Type is Int8)
      • attributes
        • contentType: qualityInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Confidence level associated with each photon event selected as signal. 0=noise. 1=added to allow for buffer but algorithm classifies as background; 2=low; 3=med; 4=high). This parameter is a 5xN array where N is the number of photons in the granule, and the 5 rows indicate signal finding for each surface type (in order: land, ocean, sea ice, land ice and inland water). Events not associated with a specific surface type have a confidence level of -1. Events evaluated as TEP returns have a confidence level of -2. (Type is String)
        • flag_meanings: possible_tep not_considered noise buffer low medium high (Type is String)
        • flag_values: -2, -1, 0, 1, 2, 3, 4 (Type is Int8)
        • long_name: Photon Signal Confidence (Type is String)
        • source: ATL03 ATBD, Section 5, Conf (Type is String)
        • units: 1 (Type is String)
        • valid_max: 4 (Type is Int8)
        • valid_min: -2 (Type is Int8)
    • ph_id_pulse[ /gt3r/heights/delta_time= 0..4548381] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The laser pulse counter is part of photon ID and counts from 1 to 200 and is reset for each new major frame. (Type is String)
        • long_name: laser pulse counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • h_ph[ /gt3r/heights/delta_time= 0..4548381] (Type is Float32)
      • attributes
        • contentType: physicalMeasurement (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Height of each received photon, relative to the WGS-84 ellipsoid including the geophysical corrections noted in Section 6. Please note that neither the geoid, ocean tide nor the dynamic atmosphere (DAC) corrections are applied to the ellipsoidal heights. (Type is String)
        • long_name: Photon WGS84 Height (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: height (Type is String)
        • units: meters (Type is String)
    • ph_id_channel[ /gt3r/heights/delta_time= 0..4548381] (Type is Byte)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Channel number assigned for each received photon event. This is part of the photon ID. Values range from 1 to 120 to span all channels and rise/fall edges. Values 1 to 60 are for falling edge; PCE1 (1 to 20), PCE 2 (21 to 40) and PCE3 (41 to 60). Values 61 to 120 are for rising edge; PCE1 (61 to 80), PCE 2 (81 to 100) and PC3 (101 to 120). (Type is String)
        • long_name: Receive channel id (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: 1 (Type is String)
        • valid_max: 120 (Type is Byte)
        • valid_min: 1 (Type is Byte)
    • lon_ph[ /gt3r/heights/delta_time= 0..4548381] (Type is Float64)
      • attributes
        • coordinates: delta_time lat_ph (Type is String)
        • description: Longitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point. (Type is String)
        • long_name: Longitude (Type is String)
        • source: ATL03g ATBD, Section 3.4 (Type is String)
        • standard_name: longitude (Type is String)
        • units: degrees_east (Type is String)
        • valid_max: 180. (Type is Float64)
        • valid_min: -180. (Type is Float64)
    • ph_id_count[ /gt3r/heights/delta_time= 0..4548381] (Type is Int8)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The photon event counter is part of photon ID and counts from 1 for each channel until reset by laser pulse counter. (Type is String)
        • long_name: photon event counter (Type is String)
        • source: Derived as part of Photon ID (Type is String)
        • units: counts (Type is String)
    • pce_mframe_cnt[ /gt3r/heights/delta_time= 0..4548381] (Type is UInt32)
      • attributes
        • contentType: referenceInformation (Type is String)
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: The major frame counter is read from the digital flow controller in a given PCE card. The counter identifies individual major frames across diag and science packets. Used as part of the photon ID. (Type is String)
        • long_name: PCE Major frame counter (Type is String)
        • source: Retained from prior a_alt_science_ph packet (Type is String)
        • units: counts (Type is String)
    • dist_ph_across[ /gt3r/heights/delta_time= 0..4548381] (Type is Float32)
      • attributes
        • coordinates: delta_time lat_ph lon_ph (Type is String)
        • description: Across-track distance projected to the ellipsoid of the received photon from the reference ground track. This is based on the Along-Track Segment algorithm described in Section 3.1. (Type is String)
        • long_name: Distance off RGT. (Type is String)
        • source: ATL03 ATBD, Section 3.1 (Type is String)
        • units: meters (Type is String)
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