Attributes { /gt1r/bckgrd_atlas/bckgrd_int_height { String contentType "modelResult"; String coordinates "delta_time"; 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."; String long_name "Altimetric range window width"; String source "ATL03 ATBD Section 7.3"; String units "meters"; } /gt1r/bckgrd_atlas/delta_time { String 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."; String long_name "Time at the start of ATLAS 50-shot sum"; String source "ATL02"; String standard_name "time"; String units "seconds since 2018-01-01"; } /gt1r/heights/lat_ph { String coordinates "delta_time lon_ph"; String description "Latitude of each received photon. Computed from the ECF Cartesian coordinates of the bounce point."; String long_name "Latitude"; String source "ATL03g ATBD, Section 3.4"; String standard_name "latitude"; String units "degrees_north"; Float64 valid_max 90.; Float64 valid_min -90.; } /gt1r/heights/delta_time { String contentType "referenceInformation"; String coordinates "lat_ph lon_ph"; 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."; String long_name "Elapsed GPS seconds"; String source "Operations"; String standard_name "time"; String units "seconds since 2018-01-01"; } gt1r { String 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."; String atlas_pce "pce3"; String atlas_beam_type "strong"; String groundtrack_id "gt1r"; String atmosphere_profile "profile_1"; String atlas_spot_number "5"; String sc_orientation "Forward"; bckgrd_atlas { } heights { } } }