| granule_type: | ATL08 |
| short_name: | ATL08 |
| level: | 3A |
| description: | Heights of ground and canopy surface at varying length scales. Where data permits, includes estimates of canopy height, relative canopy cover, canopy height distributions, surface roughness, surface slope/aspect, and apparent reflectance. |
| 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) |
| contributor_role: | Instrument Engineer, Investigator, Principle Investigator, Data Producer, Data Producer |
| Conventions: | CF-1.6 |
| date_type: | UTC |
| featureType: | trajectory |
| geospatial_lat_units: | degrees_north |
| geospatial_lon_units: | degrees_east |
| identifier_product_doi: | 10.5067/ATLAS/ATL08.001 |
| identifier_product_doi_authority: | http://dx.doi.org |
| identifier_product_type: | ATL08 |
| 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. |
| naming_authority: | http://dx.doi.org |
| spatial_coverage_type: | Horizontal |
| standard_name_vocabulary: | CF-1.6 |
| time_type: | CCSDS UTC-A |
| date_created: | 2019-05-31T07:57:46.000000Z |
| hdfversion: | HDF5 1.10.3 |
| history: | 2019-05-31T07:57:46.000000Z;6363f9ed-d6e7-3a9c-b138-f01277b075fd;Created by PGE atlas_l3a_ld Version 3.1 |
| identifier_file_uuid: | 6363f9ed-d6e7-3a9c-b138-f01277b075fd |
| identifier_product_format_version: | 3.1 |
| time_coverage_duration: | 325.00000000000000 |
| time_coverage_end: | 2019-02-23T19:24:25.000000Z |
| time_coverage_start: | 2019-02-23T19:19:00.000000Z |
| geospatial_lat_min: | 59.496067471811429 |
| geospatial_lon_min: | -158.46169300614329 |
| geospatial_lat_max: | 72.926262862851175 |
| geospatial_lon_max: | -154.27062949475274 |
| publisher_name: | NSIDC DAAC > NASA National Snow and Ice Data Center Distributed Active Archive Center |
| publisher_email: | nsidc@nsidc.org |
| publisher_url: | http://nsidc.org/daac/ |
| title: | ATLAS/ICESat-2 L3A Land and Vegetation Height |
| identifier_file_product_type: | ATL08 |
| institution: | National Aeronautics and Space Administration (NASA) |
| creator_name: | GSFC I-SIPS > ICESat-2 Science Investigator-led Processing System |
| summary: | The purpose of ATL08 is to provide along-track land/canopy heights and associated statistics. |
| keywords: | EARTH SCIENCE > BIOSPHERE > VEGETATION > NONE > NONE > NONE > NONE |
| keywords_vocabulary: | NASA/GCMD Science Keywords |
| 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. |
| processing_level: | 3A |
| references: | http://nsidc.org/data/icesat2/data.html |
| project: | ICESat-2 > Ice, Cloud, and land Elevation Satellite-2 |
| instrument: | ATLAS > Advanced Topographic Laser Altimeter System |
| platform: | ICESat-2 > Ice, Cloud, and land Elevation Satellite-2 |
| source: | Spacecraft |
| Unlimited_Dimension: | gt1l_land_segments_delta_time, gt1l_signal_photons_delta_time, gt1r_land_segments_delta_time, gt1r_signal_photons_delta_time, gt2l_land_segments_delta_time, gt2l_signal_photons_delta_time, gt2r_land_segments_delta_time, gt2r_signal_photons_delta_time, gt3l_land_segments_delta_time, gt3l_signal_photons_delta_time, gt3r_land_segments_delta_time, gt3r_signal_photons_delta_time, orbit_info_crossing_time, orbit_info_sc_orient_time |
| orbit_info_cycle_number: | Array of 16 bit Integers [orbit_info_crossing_time = 0..0] units: 1 contentType: referenceInformation long_name: Cycle Number description: A count of the number of exact repeats of this reference orbit. source: Operations valid_min: 0 valid_max: 50 origname: cycle_number fullnamepath: /orbit_info/cycle_number coordinates: orbit_info_crossing_time |
| orbit_info_orbit_number: | Array of 16 bit Unsigned integers [orbit_info_crossing_time = 0..0] units: 1 contentType: referenceInformation long_name: Orbit Number description: Unique identifying number for each planned ICESat-2 orbit. source: Operations valid_min: 1 valid_max: 65000 origname: orbit_number fullnamepath: /orbit_info/orbit_number coordinates: orbit_info_crossing_time |
| orbit_info_lan: | Array of 64 bit Reals [orbit_info_crossing_time = 0..0] units: degrees_east contentType: referenceInformation long_name: Ascending Node Longitude description: Longitude at the ascending node crossing. source: POD/PPD valid_min: -180.00000000000000 valid_max: 180.00000000000000 origname: lan fullnamepath: /orbit_info/lan coordinates: orbit_info_crossing_time |
| orbit_info_sc_orient: | Array of 16 bit Integers [orbit_info_sc_orient_time = 0..0] units: 1 contentType: referenceInformation long_name: Spacecraft Orientation 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. source: POD/PPD flag_meanings: backward forward transition flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: sc_orient fullnamepath: /orbit_info/sc_orient coordinates: orbit_info_sc_orient_time |
| orbit_info_rgt: | Array of 16 bit Integers [orbit_info_crossing_time = 0..0] units: 1 contentType: referenceInformation long_name: Reference Ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: POD/PPD valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /orbit_info/rgt coordinates: orbit_info_crossing_time |
| gt1r_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt1r_signal_photons_delta_time = 0..987773] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt1r/signal_photons/classed_pc_flag coordinates: gt1r_signal_photons_delta_time |
| gt1r_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt1r_signal_photons_delta_time = 0..987773] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt1r/signal_photons/classed_pc_indx coordinates: gt1r_signal_photons_delta_time |
| gt1r_signal_photons_d_flag: | Array of 16 bit Integers [gt1r_signal_photons_delta_time = 0..987773] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt1r/signal_photons/d_flag coordinates: gt1r_signal_photons_delta_time |
| gt1r_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt1r_signal_photons_delta_time = 0..987773] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt1r/signal_photons/ph_segment_id coordinates: gt1r_signal_photons_delta_time |
| gt1r_land_segments_segment_watermask: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt1r/land_segments/segment_watermask coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_delta_time_end: | Array of 64 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt1r/land_segments/delta_time_end coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_rgt: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt1r/land_segments/rgt coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_dem_flag: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt1r/land_segments/dem_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_msw_flag: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt1r/land_segments/msw_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_snr: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt1r/land_segments/snr coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt1r/land_segments/canopy/h_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt1r/land_segments/canopy/canopy_rh_conf coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt1r/land_segments/canopy/h_median_canopy_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt1r/land_segments/canopy/h_min_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt1r/land_segments/canopy/h_mean_canopy_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt1r/land_segments/canopy/h_median_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt1r/land_segments/canopy/h_canopy_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt1r/land_segments/canopy/toc_roughness coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt1r/land_segments/canopy/h_min_canopy_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt1r/land_segments/canopy/h_dif_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt1r/land_segments/canopy/h_canopy_quad coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt1r/land_segments/canopy/n_ca_photons coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt1r/land_segments/canopy/centroid_height coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt1r/land_segments/canopy/canopy_h_metrics_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt1r/land_segments/canopy/landsat_perc coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt1r/land_segments/canopy/h_mean_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt1r/land_segments/canopy/canopy_h_metrics coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt1r/land_segments/canopy/n_toc_photons coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt1r/land_segments/canopy/canopy_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt1r/land_segments/canopy/landsat_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt1r/land_segments/canopy/h_max_canopy_abs coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt1r/land_segments/canopy/h_canopy_uncertainty coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt1r/land_segments/canopy/canopy_openness coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt1r/land_segments/canopy/h_max_canopy coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_sigma_across: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt1r/land_segments/sigma_across coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt1r/land_segments/terrain/h_te_uncertainty coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt1r/land_segments/terrain/h_te_mean coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt1r/land_segments/terrain/h_te_min coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt1r/land_segments/terrain/h_te_interp coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt1r/land_segments/terrain/h_te_max coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt1r/land_segments/terrain/h_te_skew coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt1r/land_segments/terrain/h_te_median coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt1r/land_segments/terrain/h_te_best_fit coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt1r/land_segments/terrain/h_te_std coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt1r/land_segments/terrain/terrain_slope coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt1r/land_segments/terrain/n_te_photons coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt1r/land_segments/terrain/h_te_mode coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_segment_snowcover: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt1r/land_segments/segment_snowcover coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_beam_azimuth: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt1r/land_segments/beam_azimuth coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_solar_azimuth: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt1r/land_segments/solar_azimuth coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_psf_flag: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt1r/land_segments/psf_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_longitude: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt1r/land_segments/longitude coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude |
| gt1r_land_segments_latitude: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt1r/land_segments/latitude coordinates: gt1r_land_segments_delta_time gt1r_land_segments_longitude |
| gt1r_land_segments_segment_id_end: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt1r/land_segments/segment_id_end coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_surf_type: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt1r/land_segments/surf_type coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_segment_landcover: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt1r/land_segments/segment_landcover coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt1r/land_segments/ph_removal_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_asr: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt1r/land_segments/asr coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt1r/land_segments/sigma_atlas_land coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_segment_id_beg: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt1r/land_segments/segment_id_beg coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_sigma_along: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt1r/land_segments/sigma_along coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_dem_h: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt1r/land_segments/dem_h coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt1r/land_segments/cloud_flag_asr coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_beam_coelev: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt1r/land_segments/beam_coelev coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_sigma_topo: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt1r/land_segments/sigma_topo coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_night_flag: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt1r/land_segments/night_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_delta_time_beg: | Array of 64 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt1r/land_segments/delta_time_beg coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_sigma_h: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt1r/land_segments/sigma_h coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_last_seg_extend: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt1r/land_segments/last_seg_extend coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_atlas_pa: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt1r/land_segments/atlas_pa coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_segment_id: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt1r/land_segments/segment_id coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_solar_elevation: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt1r/land_segments/solar_elevation coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_n_seg_ph: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt1r/land_segments/n_seg_ph coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_terrain_flg: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt1r/land_segments/terrain_flg coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_urban_flag: | Array of 32 bit Integers [gt1r_land_segments_delta_time = 0..3917] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt1r/land_segments/urban_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt1r_land_segments_delta_time = 0..3917] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt1r/land_segments/dem_removal_flag coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt1r_land_segments_h_dif_ref: | Array of 32 bit Reals [gt1r_land_segments_delta_time = 0..3917] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt1r/land_segments/h_dif_ref coordinates: gt1r_land_segments_delta_time gt1r_land_segments_latitude gt1r_land_segments_longitude |
| gt2r_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt2r_signal_photons_delta_time = 0..972261] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt2r/signal_photons/classed_pc_flag coordinates: gt2r_signal_photons_delta_time |
| gt2r_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt2r_signal_photons_delta_time = 0..972261] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt2r/signal_photons/classed_pc_indx coordinates: gt2r_signal_photons_delta_time |
| gt2r_signal_photons_d_flag: | Array of 16 bit Integers [gt2r_signal_photons_delta_time = 0..972261] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt2r/signal_photons/d_flag coordinates: gt2r_signal_photons_delta_time |
| gt2r_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt2r_signal_photons_delta_time = 0..972261] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt2r/signal_photons/ph_segment_id coordinates: gt2r_signal_photons_delta_time |
| gt2r_land_segments_segment_watermask: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt2r/land_segments/segment_watermask coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_delta_time_end: | Array of 64 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt2r/land_segments/delta_time_end coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_rgt: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt2r/land_segments/rgt coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_dem_flag: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt2r/land_segments/dem_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_msw_flag: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt2r/land_segments/msw_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_snr: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt2r/land_segments/snr coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt2r/land_segments/canopy/h_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt2r/land_segments/canopy/canopy_rh_conf coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt2r/land_segments/canopy/h_median_canopy_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt2r/land_segments/canopy/h_min_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt2r/land_segments/canopy/h_mean_canopy_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt2r/land_segments/canopy/h_median_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt2r/land_segments/canopy/h_canopy_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt2r/land_segments/canopy/toc_roughness coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt2r/land_segments/canopy/h_min_canopy_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt2r/land_segments/canopy/h_dif_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt2r/land_segments/canopy/h_canopy_quad coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt2r/land_segments/canopy/n_ca_photons coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt2r/land_segments/canopy/centroid_height coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt2r/land_segments/canopy/canopy_h_metrics_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt2r/land_segments/canopy/landsat_perc coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt2r/land_segments/canopy/h_mean_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt2r/land_segments/canopy/canopy_h_metrics coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt2r/land_segments/canopy/n_toc_photons coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt2r/land_segments/canopy/canopy_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt2r/land_segments/canopy/landsat_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt2r/land_segments/canopy/h_max_canopy_abs coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt2r/land_segments/canopy/h_canopy_uncertainty coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt2r/land_segments/canopy/canopy_openness coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt2r/land_segments/canopy/h_max_canopy coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_sigma_across: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt2r/land_segments/sigma_across coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt2r/land_segments/terrain/h_te_uncertainty coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt2r/land_segments/terrain/h_te_mean coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt2r/land_segments/terrain/h_te_min coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt2r/land_segments/terrain/h_te_interp coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt2r/land_segments/terrain/h_te_max coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt2r/land_segments/terrain/h_te_skew coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt2r/land_segments/terrain/h_te_median coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt2r/land_segments/terrain/h_te_best_fit coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt2r/land_segments/terrain/h_te_std coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt2r/land_segments/terrain/terrain_slope coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt2r/land_segments/terrain/n_te_photons coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt2r/land_segments/terrain/h_te_mode coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_segment_snowcover: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt2r/land_segments/segment_snowcover coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_beam_azimuth: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt2r/land_segments/beam_azimuth coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_solar_azimuth: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt2r/land_segments/solar_azimuth coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_psf_flag: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt2r/land_segments/psf_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_longitude: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt2r/land_segments/longitude coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude |
| gt2r_land_segments_latitude: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt2r/land_segments/latitude coordinates: gt2r_land_segments_delta_time gt2r_land_segments_longitude |
| gt2r_land_segments_segment_id_end: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt2r/land_segments/segment_id_end coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_surf_type: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt2r/land_segments/surf_type coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_segment_landcover: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt2r/land_segments/segment_landcover coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt2r/land_segments/ph_removal_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_asr: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt2r/land_segments/asr coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt2r/land_segments/sigma_atlas_land coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_segment_id_beg: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt2r/land_segments/segment_id_beg coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_sigma_along: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt2r/land_segments/sigma_along coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_dem_h: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt2r/land_segments/dem_h coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt2r/land_segments/cloud_flag_asr coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_beam_coelev: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt2r/land_segments/beam_coelev coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_sigma_topo: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt2r/land_segments/sigma_topo coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_night_flag: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt2r/land_segments/night_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_delta_time_beg: | Array of 64 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt2r/land_segments/delta_time_beg coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_sigma_h: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt2r/land_segments/sigma_h coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_last_seg_extend: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt2r/land_segments/last_seg_extend coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_atlas_pa: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt2r/land_segments/atlas_pa coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_segment_id: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt2r/land_segments/segment_id coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_solar_elevation: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt2r/land_segments/solar_elevation coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_n_seg_ph: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt2r/land_segments/n_seg_ph coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_terrain_flg: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt2r/land_segments/terrain_flg coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_urban_flag: | Array of 32 bit Integers [gt2r_land_segments_delta_time = 0..3837] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt2r/land_segments/urban_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt2r_land_segments_delta_time = 0..3837] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt2r/land_segments/dem_removal_flag coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt2r_land_segments_h_dif_ref: | Array of 32 bit Reals [gt2r_land_segments_delta_time = 0..3837] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt2r/land_segments/h_dif_ref coordinates: gt2r_land_segments_delta_time gt2r_land_segments_latitude gt2r_land_segments_longitude |
| gt1l_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt1l_signal_photons_delta_time = 0..3446216] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt1l/signal_photons/classed_pc_flag coordinates: gt1l_signal_photons_delta_time |
| gt1l_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt1l_signal_photons_delta_time = 0..3446216] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt1l/signal_photons/classed_pc_indx coordinates: gt1l_signal_photons_delta_time |
| gt1l_signal_photons_d_flag: | Array of 16 bit Integers [gt1l_signal_photons_delta_time = 0..3446216] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt1l/signal_photons/d_flag coordinates: gt1l_signal_photons_delta_time |
| gt1l_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt1l_signal_photons_delta_time = 0..3446216] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt1l/signal_photons/ph_segment_id coordinates: gt1l_signal_photons_delta_time |
| gt1l_land_segments_segment_watermask: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt1l/land_segments/segment_watermask coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_delta_time_end: | Array of 64 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt1l/land_segments/delta_time_end coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_rgt: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt1l/land_segments/rgt coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_dem_flag: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt1l/land_segments/dem_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_msw_flag: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt1l/land_segments/msw_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_snr: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt1l/land_segments/snr coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt1l/land_segments/canopy/h_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt1l/land_segments/canopy/canopy_rh_conf coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt1l/land_segments/canopy/h_median_canopy_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt1l/land_segments/canopy/h_min_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt1l/land_segments/canopy/h_mean_canopy_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt1l/land_segments/canopy/h_median_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt1l/land_segments/canopy/h_canopy_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt1l/land_segments/canopy/toc_roughness coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt1l/land_segments/canopy/h_min_canopy_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt1l/land_segments/canopy/h_dif_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt1l/land_segments/canopy/h_canopy_quad coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt1l/land_segments/canopy/n_ca_photons coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt1l/land_segments/canopy/centroid_height coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt1l/land_segments/canopy/canopy_h_metrics_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt1l/land_segments/canopy/landsat_perc coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt1l/land_segments/canopy/h_mean_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt1l/land_segments/canopy/canopy_h_metrics coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt1l/land_segments/canopy/n_toc_photons coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt1l/land_segments/canopy/canopy_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt1l/land_segments/canopy/landsat_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt1l/land_segments/canopy/h_max_canopy_abs coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt1l/land_segments/canopy/h_canopy_uncertainty coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt1l/land_segments/canopy/canopy_openness coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt1l/land_segments/canopy/h_max_canopy coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_sigma_across: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt1l/land_segments/sigma_across coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt1l/land_segments/terrain/h_te_uncertainty coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt1l/land_segments/terrain/h_te_mean coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt1l/land_segments/terrain/h_te_min coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt1l/land_segments/terrain/h_te_interp coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt1l/land_segments/terrain/h_te_max coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt1l/land_segments/terrain/h_te_skew coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt1l/land_segments/terrain/h_te_median coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt1l/land_segments/terrain/h_te_best_fit coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt1l/land_segments/terrain/h_te_std coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt1l/land_segments/terrain/terrain_slope coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt1l/land_segments/terrain/n_te_photons coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt1l/land_segments/terrain/h_te_mode coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_segment_snowcover: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt1l/land_segments/segment_snowcover coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_beam_azimuth: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt1l/land_segments/beam_azimuth coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_solar_azimuth: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt1l/land_segments/solar_azimuth coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_psf_flag: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt1l/land_segments/psf_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_longitude: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt1l/land_segments/longitude coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude |
| gt1l_land_segments_latitude: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt1l/land_segments/latitude coordinates: gt1l_land_segments_delta_time gt1l_land_segments_longitude |
| gt1l_land_segments_segment_id_end: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt1l/land_segments/segment_id_end coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_surf_type: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt1l/land_segments/surf_type coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_segment_landcover: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt1l/land_segments/segment_landcover coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt1l/land_segments/ph_removal_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_asr: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt1l/land_segments/asr coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt1l/land_segments/sigma_atlas_land coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_segment_id_beg: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt1l/land_segments/segment_id_beg coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_sigma_along: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt1l/land_segments/sigma_along coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_dem_h: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt1l/land_segments/dem_h coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt1l/land_segments/cloud_flag_asr coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_beam_coelev: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt1l/land_segments/beam_coelev coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_sigma_topo: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt1l/land_segments/sigma_topo coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_night_flag: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt1l/land_segments/night_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_delta_time_beg: | Array of 64 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt1l/land_segments/delta_time_beg coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_sigma_h: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt1l/land_segments/sigma_h coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_last_seg_extend: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt1l/land_segments/last_seg_extend coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_atlas_pa: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt1l/land_segments/atlas_pa coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_segment_id: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt1l/land_segments/segment_id coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_solar_elevation: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt1l/land_segments/solar_elevation coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_n_seg_ph: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt1l/land_segments/n_seg_ph coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_terrain_flg: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt1l/land_segments/terrain_flg coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_urban_flag: | Array of 32 bit Integers [gt1l_land_segments_delta_time = 0..4981] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt1l/land_segments/urban_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt1l_land_segments_delta_time = 0..4981] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt1l/land_segments/dem_removal_flag coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| gt1l_land_segments_h_dif_ref: | Array of 32 bit Reals [gt1l_land_segments_delta_time = 0..4981] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt1l/land_segments/h_dif_ref coordinates: gt1l_land_segments_delta_time gt1l_land_segments_latitude gt1l_land_segments_longitude |
| quality_assessment_qa_granule_fail_reason: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: qualityInformation long_name: Granule Failure Reason 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. source: Operations flag_meanings: no_failure PROCESS_ERROR INSUFFICIENT_OUTPUT failure_3 failure_4 OTHER_FAILURE flag_values: 0, 1, 2, 3, 4, 5 valid_min: 0 valid_max: 5 origname: qa_granule_fail_reason fullnamepath: /quality_assessment/qa_granule_fail_reason |
| quality_assessment_qa_granule_pass_fail: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: qualityInformation long_name: Granule Pass Flag description: Flag indicating granule quality. 0=granule passes automatic QA. 1=granule fails automatic QA. source: Operations flag_meanings: PASS FAIL flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: qa_granule_pass_fail fullnamepath: /quality_assessment/qa_granule_pass_fail |
| gt3l_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt3l_signal_photons_delta_time = 0..3319973] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt3l/signal_photons/classed_pc_flag coordinates: gt3l_signal_photons_delta_time |
| gt3l_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt3l_signal_photons_delta_time = 0..3319973] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt3l/signal_photons/classed_pc_indx coordinates: gt3l_signal_photons_delta_time |
| gt3l_signal_photons_d_flag: | Array of 16 bit Integers [gt3l_signal_photons_delta_time = 0..3319973] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt3l/signal_photons/d_flag coordinates: gt3l_signal_photons_delta_time |
| gt3l_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt3l_signal_photons_delta_time = 0..3319973] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt3l/signal_photons/ph_segment_id coordinates: gt3l_signal_photons_delta_time |
| gt3l_land_segments_segment_watermask: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt3l/land_segments/segment_watermask coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_delta_time_end: | Array of 64 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt3l/land_segments/delta_time_end coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_rgt: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt3l/land_segments/rgt coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_dem_flag: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt3l/land_segments/dem_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_msw_flag: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt3l/land_segments/msw_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_snr: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt3l/land_segments/snr coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt3l/land_segments/canopy/h_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt3l/land_segments/canopy/canopy_rh_conf coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt3l/land_segments/canopy/h_median_canopy_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt3l/land_segments/canopy/h_min_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt3l/land_segments/canopy/h_mean_canopy_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt3l/land_segments/canopy/h_median_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt3l/land_segments/canopy/h_canopy_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt3l/land_segments/canopy/toc_roughness coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt3l/land_segments/canopy/h_min_canopy_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt3l/land_segments/canopy/h_dif_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt3l/land_segments/canopy/h_canopy_quad coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt3l/land_segments/canopy/n_ca_photons coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt3l/land_segments/canopy/centroid_height coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt3l/land_segments/canopy/canopy_h_metrics_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt3l/land_segments/canopy/landsat_perc coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt3l/land_segments/canopy/h_mean_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt3l/land_segments/canopy/canopy_h_metrics coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt3l/land_segments/canopy/n_toc_photons coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt3l/land_segments/canopy/canopy_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt3l/land_segments/canopy/landsat_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt3l/land_segments/canopy/h_max_canopy_abs coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt3l/land_segments/canopy/h_canopy_uncertainty coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt3l/land_segments/canopy/canopy_openness coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt3l/land_segments/canopy/h_max_canopy coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_sigma_across: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt3l/land_segments/sigma_across coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt3l/land_segments/terrain/h_te_uncertainty coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt3l/land_segments/terrain/h_te_mean coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt3l/land_segments/terrain/h_te_min coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt3l/land_segments/terrain/h_te_interp coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt3l/land_segments/terrain/h_te_max coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt3l/land_segments/terrain/h_te_skew coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt3l/land_segments/terrain/h_te_median coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt3l/land_segments/terrain/h_te_best_fit coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt3l/land_segments/terrain/h_te_std coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt3l/land_segments/terrain/terrain_slope coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt3l/land_segments/terrain/n_te_photons coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt3l/land_segments/terrain/h_te_mode coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_segment_snowcover: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt3l/land_segments/segment_snowcover coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_beam_azimuth: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt3l/land_segments/beam_azimuth coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_solar_azimuth: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt3l/land_segments/solar_azimuth coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_psf_flag: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt3l/land_segments/psf_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_longitude: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt3l/land_segments/longitude coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude |
| gt3l_land_segments_latitude: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt3l/land_segments/latitude coordinates: gt3l_land_segments_delta_time gt3l_land_segments_longitude |
| gt3l_land_segments_segment_id_end: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt3l/land_segments/segment_id_end coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_surf_type: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt3l/land_segments/surf_type coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_segment_landcover: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt3l/land_segments/segment_landcover coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt3l/land_segments/ph_removal_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_asr: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt3l/land_segments/asr coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt3l/land_segments/sigma_atlas_land coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_segment_id_beg: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt3l/land_segments/segment_id_beg coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_sigma_along: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt3l/land_segments/sigma_along coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_dem_h: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt3l/land_segments/dem_h coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt3l/land_segments/cloud_flag_asr coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_beam_coelev: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt3l/land_segments/beam_coelev coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_sigma_topo: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt3l/land_segments/sigma_topo coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_night_flag: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt3l/land_segments/night_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_delta_time_beg: | Array of 64 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt3l/land_segments/delta_time_beg coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_sigma_h: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt3l/land_segments/sigma_h coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_last_seg_extend: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt3l/land_segments/last_seg_extend coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_atlas_pa: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt3l/land_segments/atlas_pa coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_segment_id: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt3l/land_segments/segment_id coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_solar_elevation: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt3l/land_segments/solar_elevation coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_n_seg_ph: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt3l/land_segments/n_seg_ph coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_terrain_flg: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt3l/land_segments/terrain_flg coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_urban_flag: | Array of 32 bit Integers [gt3l_land_segments_delta_time = 0..4926] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt3l/land_segments/urban_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt3l_land_segments_delta_time = 0..4926] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt3l/land_segments/dem_removal_flag coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt3l_land_segments_h_dif_ref: | Array of 32 bit Reals [gt3l_land_segments_delta_time = 0..4926] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt3l/land_segments/h_dif_ref coordinates: gt3l_land_segments_delta_time gt3l_land_segments_latitude gt3l_land_segments_longitude |
| gt2l_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt2l_signal_photons_delta_time = 0..2717621] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt2l/signal_photons/classed_pc_flag coordinates: gt2l_signal_photons_delta_time |
| gt2l_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt2l_signal_photons_delta_time = 0..2717621] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt2l/signal_photons/classed_pc_indx coordinates: gt2l_signal_photons_delta_time |
| gt2l_signal_photons_d_flag: | Array of 16 bit Integers [gt2l_signal_photons_delta_time = 0..2717621] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt2l/signal_photons/d_flag coordinates: gt2l_signal_photons_delta_time |
| gt2l_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt2l_signal_photons_delta_time = 0..2717621] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt2l/signal_photons/ph_segment_id coordinates: gt2l_signal_photons_delta_time |
| gt2l_land_segments_segment_watermask: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt2l/land_segments/segment_watermask coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_delta_time_end: | Array of 64 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt2l/land_segments/delta_time_end coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_rgt: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt2l/land_segments/rgt coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_dem_flag: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt2l/land_segments/dem_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_msw_flag: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt2l/land_segments/msw_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_snr: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt2l/land_segments/snr coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt2l/land_segments/canopy/h_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt2l/land_segments/canopy/canopy_rh_conf coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt2l/land_segments/canopy/h_median_canopy_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt2l/land_segments/canopy/h_min_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt2l/land_segments/canopy/h_mean_canopy_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt2l/land_segments/canopy/h_median_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt2l/land_segments/canopy/h_canopy_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt2l/land_segments/canopy/toc_roughness coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt2l/land_segments/canopy/h_min_canopy_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt2l/land_segments/canopy/h_dif_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt2l/land_segments/canopy/h_canopy_quad coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt2l/land_segments/canopy/n_ca_photons coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt2l/land_segments/canopy/centroid_height coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt2l/land_segments/canopy/canopy_h_metrics_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt2l/land_segments/canopy/landsat_perc coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt2l/land_segments/canopy/h_mean_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt2l/land_segments/canopy/canopy_h_metrics coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt2l/land_segments/canopy/n_toc_photons coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt2l/land_segments/canopy/canopy_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt2l/land_segments/canopy/landsat_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt2l/land_segments/canopy/h_max_canopy_abs coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt2l/land_segments/canopy/h_canopy_uncertainty coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt2l/land_segments/canopy/canopy_openness coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt2l/land_segments/canopy/h_max_canopy coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_sigma_across: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt2l/land_segments/sigma_across coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt2l/land_segments/terrain/h_te_uncertainty coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt2l/land_segments/terrain/h_te_mean coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt2l/land_segments/terrain/h_te_min coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt2l/land_segments/terrain/h_te_interp coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt2l/land_segments/terrain/h_te_max coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt2l/land_segments/terrain/h_te_skew coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt2l/land_segments/terrain/h_te_median coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt2l/land_segments/terrain/h_te_best_fit coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt2l/land_segments/terrain/h_te_std coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt2l/land_segments/terrain/terrain_slope coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt2l/land_segments/terrain/n_te_photons coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt2l/land_segments/terrain/h_te_mode coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_segment_snowcover: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt2l/land_segments/segment_snowcover coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_beam_azimuth: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt2l/land_segments/beam_azimuth coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_solar_azimuth: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt2l/land_segments/solar_azimuth coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_psf_flag: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt2l/land_segments/psf_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_longitude: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt2l/land_segments/longitude coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude |
| gt2l_land_segments_latitude: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt2l/land_segments/latitude coordinates: gt2l_land_segments_delta_time gt2l_land_segments_longitude |
| gt2l_land_segments_segment_id_end: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt2l/land_segments/segment_id_end coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_surf_type: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt2l/land_segments/surf_type coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_segment_landcover: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt2l/land_segments/segment_landcover coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt2l/land_segments/ph_removal_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_asr: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt2l/land_segments/asr coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt2l/land_segments/sigma_atlas_land coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_segment_id_beg: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt2l/land_segments/segment_id_beg coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_sigma_along: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt2l/land_segments/sigma_along coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_dem_h: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt2l/land_segments/dem_h coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt2l/land_segments/cloud_flag_asr coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_beam_coelev: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt2l/land_segments/beam_coelev coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_sigma_topo: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt2l/land_segments/sigma_topo coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_night_flag: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt2l/land_segments/night_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_delta_time_beg: | Array of 64 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt2l/land_segments/delta_time_beg coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_sigma_h: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt2l/land_segments/sigma_h coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_last_seg_extend: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt2l/land_segments/last_seg_extend coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_atlas_pa: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt2l/land_segments/atlas_pa coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_segment_id: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt2l/land_segments/segment_id coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_solar_elevation: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt2l/land_segments/solar_elevation coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_n_seg_ph: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt2l/land_segments/n_seg_ph coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_terrain_flg: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt2l/land_segments/terrain_flg coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_urban_flag: | Array of 32 bit Integers [gt2l_land_segments_delta_time = 0..4623] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt2l/land_segments/urban_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt2l_land_segments_delta_time = 0..4623] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt2l/land_segments/dem_removal_flag coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| gt2l_land_segments_h_dif_ref: | Array of 32 bit Reals [gt2l_land_segments_delta_time = 0..4623] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt2l/land_segments/h_dif_ref coordinates: gt2l_land_segments_delta_time gt2l_land_segments_latitude gt2l_land_segments_longitude |
| ancillary_data_release: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Release Number 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. source: Operations origname: release fullnamepath: /ancillary_data/release |
| ancillary_data_end_geoseg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Ending Geolocation Segment 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. source: Derived origname: end_geoseg fullnamepath: /ancillary_data/end_geoseg |
| ancillary_data_version: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Version 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. source: Operations origname: version fullnamepath: /ancillary_data/version |
| ancillary_data_end_region: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Ending Region 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. source: Derived origname: end_region fullnamepath: /ancillary_data/end_region |
| ancillary_data_atlas_sdp_gps_epoch: | Array of 64 bit Reals [FakeDim0 = 0..0] units: seconds since 1980-01-06T00:00:00.000000Z contentType: auxiliaryInformation long_name: ATLAS Epoch Offset 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. source: Operations origname: atlas_sdp_gps_epoch fullnamepath: /ancillary_data/atlas_sdp_gps_epoch |
| ancillary_data_end_rgt: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Ending Reference Groundtrack 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. source: Derived valid_min: 1 valid_max: 1387 origname: end_rgt fullnamepath: /ancillary_data/end_rgt |
| ancillary_data_end_delta_time: | Array of 64 bit Reals [FakeDim0 = 0..0] units: seconds since 2018-01-01 contentType: auxiliaryInformation long_name: ATLAS End Time (Actual) standard_name: time 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. source: Derived origname: end_delta_time fullnamepath: /ancillary_data/end_delta_time |
| ancillary_data_end_orbit: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Ending Orbit Number 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. source: Derived origname: end_orbit fullnamepath: /ancillary_data/end_orbit |
| ancillary_data_start_cycle: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Starting Cycle 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. source: Derived valid_min: 0 valid_max: 99 origname: start_cycle fullnamepath: /ancillary_data/start_cycle |
| ancillary_data_data_end_utc: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: End UTC Time of Granule (CCSDS-A, Actual) description: UTC (in CCSDS-A format) of the last data point within the granule. source: Derived origname: data_end_utc fullnamepath: /ancillary_data/data_end_utc |
| ancillary_data_control: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Control File description: PGE-specific control file used to generate this granule. To re-use, replace breaks (BR) with linefeeds. source: Operations origname: control fullnamepath: /ancillary_data/control |
| ancillary_data_start_gpssow: | Array of 64 bit Reals [FakeDim0 = 0..0] units: seconds contentType: auxiliaryInformation long_name: Start GPS SOW of Granule (Actual) description: GPS seconds-of-week of the first data point in the granule. source: Derived origname: start_gpssow fullnamepath: /ancillary_data/start_gpssow |
| ancillary_data_granule_end_utc: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: End UTC Time of Granule (CCSDS-A, Requested) description: Requested end time (in UTC CCSDS-A) of this granule. source: Derived origname: granule_end_utc fullnamepath: /ancillary_data/granule_end_utc |
| ancillary_data_end_cycle: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Ending Cycle 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. source: Derived valid_min: 0 valid_max: 99 origname: end_cycle fullnamepath: /ancillary_data/end_cycle |
| ancillary_data_granule_start_utc: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Start UTC Time of Granule (CCSDS-A, Requested) description: Requested start time (in UTC CCSDS-A) of this granule. source: Derived origname: granule_start_utc fullnamepath: /ancillary_data/granule_start_utc |
| ancillary_data_land_ca_class: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Canopy class value description: Canopy classification flag value. (Default = 2) source: ATBD section 4.12 step 1 origname: ca_class fullnamepath: /ancillary_data/land/ca_class |
| ancillary_data_land_canopy_flag_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation description: Controls entrance to the canopy flag subroutine . (Default = 1) source: ATBD section 4.3 long_name: canopy_flag switch origname: canopy_flag_switch fullnamepath: /ancillary_data/land/canopy_flag_switch |
| ancillary_data_land_up_toc_bnd: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Upper bound restricting the search of a top of canopy surface. description: Upper bound restricting the search of a top of canopy surface. (Default=1.0) source: ATBD section 4.7 step 3 entered from section 4.8 origname: up_toc_bnd fullnamepath: /ancillary_data/land/up_toc_bnd |
| ancillary_data_land_fnlgnd_filter_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: finalground filter switch description: Controls filtering based on FINALGROUND. (Default = 1) source: ATBD section 4.13 step 2 origname: fnlgnd_filter_switch fullnamepath: /ancillary_data/land/fnlgnd_filter_switch |
| ancillary_data_land_psf: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Point Spread Function description: Parameter controlling identification of photons around an interpolated surface. (Default = 0.5) source: ATBD section 4.7 step 12 origname: psf fullnamepath: /ancillary_data/land/psf |
| ancillary_data_land_dem_removal_percent_limit: | Array of 32 bit Reals [FakeDim0 = 0..0] units: percent contentType: auxiliaryInformation long_name: dem_removal_flag set threshold description: Percent of photons in land segment failing DEM test to set dem_removal_flag. (default = 20.0) source: ATBD section 2.4.11 origname: dem_removal_percent_limit fullnamepath: /ancillary_data/land/dem_removal_percent_limit |
| ancillary_data_land_atl08_region: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: modelResult long_name: atl08 region standard_name: atl08_region description: ATL08 region(s) encompassed by ATL03 granule being processed source: Land ATBD 29March2019, Table 2.4 origname: atl08_region fullnamepath: /ancillary_data/land/atl08_region |
| ancillary_data_land_can_noise_thresh: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold for reclassification of canopy as noise description: Threshold, as a number of canopy photons in the CAN_FILT_SEG, used for the reclassification of canopy signal photons. (Default = 75) source: ATBD section 4.11 step 6 origname: can_noise_thresh fullnamepath: /ancillary_data/land/can_noise_thresh |
| ancillary_data_land_relief_hbot: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation description: The approximate relief of the L-km segment uses the percentile height values, relief_htop and relief_hbot. (Default=0.05) source: ATBD (section 4.5 step 6) long_name: lower relief percentile origname: relief_hbot fullnamepath: /ancillary_data/land/relief_hbot |
| ancillary_data_land_dem_filter_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: dem_filter switch description: Controls filtering based on DEM. (Default = 1) source: ATBD section 4.5 step 5 origname: dem_filter_switch fullnamepath: /ancillary_data/land/dem_filter_switch |
| ancillary_data_land_relief_htop: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Upper relief percentile description: The approximate relief of the L-km segment uses the percentile height values, relief_htop and relief_hbot. (Default=0.95) source: ATBD (section 4.5 step 6) origname: relief_htop fullnamepath: /ancillary_data/land/relief_htop |
| ancillary_data_land_dseg_buf: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: DRAGANN segment buffer size description: DRAGANN segment buffer length in 20m geolocated segments along ground track. (Default=10) source: ATBD section 4.2.1 step 1 origname: dseg_buf fullnamepath: /ancillary_data/land/dseg_buf |
| ancillary_data_land_night_thresh: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold for night description: Solar elevation threshold for determining night time conditions. (Default =0.0) source: ATBD section 2.4.9 origname: night_thresh fullnamepath: /ancillary_data/land/night_thresh |
| ancillary_data_land_h_canopy_perc: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: h_canopy percentile description: Percentile component of h_canopy parameter. (Default =0.95) source: ATBD section 2.2.3 origname: h_canopy_perc fullnamepath: /ancillary_data/land/h_canopy_perc |
| ancillary_data_land_up_filt_bnd: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Proportionality coefficient for controlling the bounds of the filter window size as a function of number of signal photons. description: Lower bound of the filter window size function. (Default = 46) source: ATBD section 4.4 step 2 origname: up_filt_bnd fullnamepath: /ancillary_data/land/up_filt_bnd |
| ancillary_data_land_lw_filt_bnd: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Proportionality coefficient for controlling the bounds of the filter window size as a function of number of signal photons. description: Lower bound of the filter window size function. (Default = 5) source: ATBD section 4.4 step 2 origname: lw_filt_bnd fullnamepath: /ancillary_data/land/lw_filt_bnd |
| ancillary_data_land_ph_removal_percent_limit: | Array of 32 bit Reals [FakeDim0 = 0..0] units: percent contentType: auxiliaryInformation long_name: ph_removal_flag set threshold description: Percent of photons in land segment removed to set ph_removal_flag. (default = 50.0) source: ATBD section 4.13 step 4 origname: ph_removal_percent_limit fullnamepath: /ancillary_data/land/ph_removal_percent_limit |
| ancillary_data_land_canopy_seg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: segment size in canopy filter description: Segment in number of signal photons for filtering sparse canopy cover. (Default = 500) source: ATBD section 4.11 step 6 origname: canopy_seg fullnamepath: /ancillary_data/land/canopy_seg |
| ancillary_data_land_max_try: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation description: Maximum number of tries to compute a P value in alternative DRAGANN source: ATBD section 4.2.1 step 17 long_name: Maximum try count origname: max_try fullnamepath: /ancillary_data/land/max_try |
| ancillary_data_land_bin_size_n: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: neighbor histogram bin size description: Size of neighbor histogram bins in number of neighbors in DRAGANN. (Default = 1) source: ATBD (section 4.2 step 4) origname: bin_size_n fullnamepath: /ancillary_data/land/bin_size_n |
| ancillary_data_land_lw_gnd_bnd: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Lower bound restricting the search of a ground surface in canopy cases. description: Lower bound restricting the search of a ground surface in canopy cases. (Default = -4.0) source: ATBD section 4.7 step 3 origname: lw_gnd_bnd fullnamepath: /ancillary_data/land/lw_gnd_bnd |
| ancillary_data_land_del_mu: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Step size for optimizing the mean parameter of Gaussian function. description: Step size for optimizing the mean parameter of Gaussian function. (Default = 0.2) source: ATBD section 4.2 step 7 origname: del_mu fullnamepath: /ancillary_data/land/del_mu |
| ancillary_data_land_lw_toc_cut: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Lower cutoff for top of canopy description: Lower cutoff for top of canopy surface. (Default = 2.0) source: ATBD section 4.8 step 10 origname: lw_toc_cut fullnamepath: /ancillary_data/land/lw_toc_cut |
| ancillary_data_land_class_thresh: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold flag value for classification of photons as signal via input from ATL03 description: Threshold flag value for classification of photons as signal via input from ATL03. (Default =3) source: ATBD section 4.2 step 17 origname: class_thresh fullnamepath: /ancillary_data/land/class_thresh |
| ancillary_data_land_lseg_buf: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Long segment buffer size description: Overlapping long segment buffer size in 20m geosegments along ground track. (Default=10) source: ATBD section 4.1 step 2 origname: lseg_buf fullnamepath: /ancillary_data/land/lseg_buf |
| ancillary_data_land_lw_toc_bnd: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Lower bound restricting the search of a top of canopy surface. description: Lower bound restricting the search of a top of canopy surface. (Default = -4.0) source: section 4.7 step 3 entered from section 4.8 origname: lw_toc_bnd fullnamepath: /ancillary_data/land/lw_toc_bnd |
| ancillary_data_land_up_toc_cut: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: upper cutoff of top of canopy surface. description: Upper cutoff for top of canopy surface. (Default = 150.0) source: ATBD section 4.8 step 10 origname: up_toc_cut fullnamepath: /ancillary_data/land/up_toc_cut |
| ancillary_data_land_gnd_stat_thresh: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold for terrain statistics description: Minimum percentage of terrain photons to compute statistics upon. (Default =0.05) source: ATBD section 4.13 step 2 origname: gnd_stat_thresh fullnamepath: /ancillary_data/land/gnd_stat_thresh |
| ancillary_data_land_iter_max: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Maximum number of iterations for optimizing the Gaussian parameters for fitting of histogram. description: Maximum number of iterations for optimizing the Gaussian parameters for fitting of histogram. (Default = 10) source: ATBD section 4.2 step 7 origname: iter_max fullnamepath: /ancillary_data/land/iter_max |
| ancillary_data_land_gthresh_factor: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: threshold for Gaussian Elimination description: Controls threshold for Gaussian Elimination. (Default = 0.1) source: ATBD sGaussian Rejection section of Appendix A origname: gthresh_factor fullnamepath: /ancillary_data/land/gthresh_factor |
| ancillary_data_land_dseg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: DRAGANN segment size description: DRAGANN segment length in 20m geolocated segments along ground track. (Default=170) source: ATBD section 4.2.1 step 1 origname: dseg fullnamepath: /ancillary_data/land/dseg |
| ancillary_data_land_bin_size_h: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: neighbor histogram bin size description: Histogram bin size for the alternative DRAGANN algorithm. (Default = 1.0) source: ATBD (section 4.2.1 step 3) origname: bin_size_h fullnamepath: /ancillary_data/land/bin_size_h |
| ancillary_data_land_up_gnd_bnd: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Upper bound restricting the search of a ground surface in canopy cases. description: Upper bound restricting the search of a ground surface in canopy cases. (Default = 1.0) source: ATBD (section 4.7 step 3) origname: up_gnd_bnd fullnamepath: /ancillary_data/land/up_gnd_bnd |
| ancillary_data_land_min_nphs: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Minimum input photons description: Minimum number of input photons from ATL03 to process. (default=1) source: Operations origname: min_nphs fullnamepath: /ancillary_data/land/min_nphs |
| ancillary_data_land_tc_thresh: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Canopy Flag threshold description: Percentage threshold for average L-km segment tree cover to be considered canopy. (Default = 5.0) source: ATBD section 4.3 steps 6 and 7 origname: tc_thresh fullnamepath: /ancillary_data/land/tc_thresh |
| ancillary_data_land_te_class: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Terrain class value description: Terrain classification flag value. (Default = 1) source: ATBD section 4.12 step 1 origname: te_class fullnamepath: /ancillary_data/land/te_class |
| ancillary_data_land_toc_class: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Top of canopy class value description: Top of canopy classification flag value. (Default = 3) source: ATBD section 4.12 step 1 origname: toc_class fullnamepath: /ancillary_data/land/toc_class |
| ancillary_data_land_iter_gnd: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Iterations of smoothing of interpolated ground surface for ground estimate. description: Iterations of smoothing of interpolated ground surface for refinement. (Default = 10) source: ATBD section 4.10 step 1 origname: iter_gnd fullnamepath: /ancillary_data/land/iter_gnd |
| ancillary_data_land_max_atl03files: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Maximum number of input ATL03s description: Maximum number of input ATL03 files. (Default = 200) source: Operations origname: max_atl03files fullnamepath: /ancillary_data/land/max_atl03files |
| ancillary_data_land_noise_class: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Noise class value description: Noise classification flag value. (Default = 0) source: ATBD section 4.12 step 1 origname: noise_class fullnamepath: /ancillary_data/land/noise_class |
| ancillary_data_land_outlier_filter_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: outlier_filter switch description: Controls entrance to the outlier filter subroutine. (Default = 1) source: ATBD section 4.6 origname: outlier_filter_switch fullnamepath: /ancillary_data/land/outlier_filter_switch |
| ancillary_data_land_dragann_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: DRAGANN switch description: Controls entrance to the DRAGANN subroutine. (Default =1) source: ATBD section 4.2 origname: dragann_switch fullnamepath: /ancillary_data/land/dragann_switch |
| ancillary_data_land_proc_geoseg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Geosegment process interval length description: Geosegment process interval length. This controls the amount read from ATL03 and ATL09 at a time. (Default = 500000). source: Operations origname: proc_geoseg fullnamepath: /ancillary_data/land/proc_geoseg |
| ancillary_data_land_can_stat_thresh: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold for canopy statistics description: Minimum percentage of canopy photons to compute statistics upon. (Default =0.05) source: ATBD section 4.14.1 step 1 origname: can_stat_thresh fullnamepath: /ancillary_data/land/can_stat_thresh |
| ancillary_data_land_lseg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Long segment size description: Long segment size in number of 20 meter segments along ground track. (Default=500) source: ATBD section 4.1 step 1 origname: lseg fullnamepath: /ancillary_data/land/lseg |
| ancillary_data_land_max_atl09files: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Maximum number of input ATL09s description: Maximum number of input ATL09 files. (Default = 200) source: Operations origname: max_atl09files fullnamepath: /ancillary_data/land/max_atl09files |
| ancillary_data_land_ref_dem_limit: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: DEM threshold description: Reference DEM limit used to reclassify signal as noise. (default = 120.0) source: ATBD section 4.5 step 4 origname: ref_dem_limit fullnamepath: /ancillary_data/land/ref_dem_limit |
| ancillary_data_land_max_peaks: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Maximum number of Gaussian peaks to fit in the data set description: Maximum number of Gaussian peaks to fit in the data set in DRAGANN. (Default =10) source: ATBD section 4.2 step 9 origname: max_peaks fullnamepath: /ancillary_data/land/max_peaks |
| ancillary_data_land_stat_thresh: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Threshold for land statistics description: Minimum number of photons to compute statistics upon. (Default =50) source: ATBD section 2 intro paragraph origname: stat_thresh fullnamepath: /ancillary_data/land/stat_thresh |
| ancillary_data_land_sig_rsq_search: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters^2 contentType: auxiliaryInformation long_name: Square Radius of filter for canopy description: Top of canopy refinement square search radius. (Default = 225.0) source: ATBD section 4.8 step 6 origname: sig_rsq_search fullnamepath: /ancillary_data/land/sig_rsq_search |
| ancillary_data_land_del_amp: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Step Gaussian Amplitude optimization description: Step size for optimizing the amplitude variable of Gaussian function. (Default = 1.0) source: ATBD section 4.2 step 7 origname: del_amp fullnamepath: /ancillary_data/land/del_amp |
| ancillary_data_land_sseg: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: Short Segment Length description: Short segment length in meters. (Default = 100.0) source: ATBD section 4.13 step 1 origname: sseg fullnamepath: /ancillary_data/land/sseg |
| ancillary_data_land_shp_param: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Exponential coefficient for controlling the exponential decay of the filter window size as a function of number of signal photons. description: Exponential coefficient of the filter window size as a function. (Default = 21.0E-06) source: ATBD section 4.4 step 2 origname: shp_param fullnamepath: /ancillary_data/land/shp_param |
| ancillary_data_land_del_sigma: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Step size for optimizing the standard deviation parameter of Gaussian function. description: Step size for optimizing the standard deviation parameter of Gaussian function. (Default = 0.5) source: ATBD section 4.2 step 7 origname: del_sigma fullnamepath: /ancillary_data/land/del_sigma |
| ancillary_data_land_cloud_filter_switch: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: cloud_filter switch description: Controls entrance to the cloud_filter subroutine. (Default = 0) source: ATBD section 4.1.1 origname: cloud_filter_switch fullnamepath: /ancillary_data/land/cloud_filter_switch |
| ancillary_data_land_n_dec_mode: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Mode decimal parameter description: Number of decimal places to consider in mode computation. (Default =1) source: ATBD needed for section 4.13 step 3(h_te_mode) origname: n_dec_mode fullnamepath: /ancillary_data/land/n_dec_mode |
| ancillary_data_land_ref_finalground_limit: | Array of 32 bit Reals [FakeDim0 = 0..0] units: meters contentType: auxiliaryInformation long_name: finalground threshold description: Reference finalground limit used to reclassify signal as noise. (default = 150.0) source: ATBD section 4.13 step 2 origname: ref_finalground_limit fullnamepath: /ancillary_data/land/ref_finalground_limit |
| ancillary_data_land_p_static: | Array of 32 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Dragann Parameter description: Parameter for controlling the search radius in nearest neighbor search in DRAGANN. (Default = 20) source: ATBD section 4.2 step 1 origname: p_static fullnamepath: /ancillary_data/land/p_static |
| ancillary_data_start_delta_time: | Array of 64 bit Reals [FakeDim0 = 0..0] units: seconds since 2018-01-01 contentType: auxiliaryInformation long_name: ATLAS Start Time (Actual) standard_name: time 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. source: Derived origname: start_delta_time fullnamepath: /ancillary_data/start_delta_time |
| ancillary_data_start_geoseg: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Starting Geolocation Segment 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. source: Derived origname: start_geoseg fullnamepath: /ancillary_data/start_geoseg |
| ancillary_data_start_orbit: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Starting Orbit Number 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. source: Derived origname: start_orbit fullnamepath: /ancillary_data/start_orbit |
| ancillary_data_data_start_utc: | Array of Strings [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Start UTC Time of Granule (CCSDS-A, Actual) description: UTC (in CCSDS-A format) of the first data point within the granule. source: Derived origname: data_start_utc fullnamepath: /ancillary_data/data_start_utc |
| ancillary_data_end_gpsweek: | Array of 32 bit Integers [FakeDim0 = 0..0] units: weeks from 1980-01-06 contentType: auxiliaryInformation long_name: Ending GPSWeek of Granule (Actual) description: GPS week number of the last data point in the granule. source: Derived origname: end_gpsweek fullnamepath: /ancillary_data/end_gpsweek |
| ancillary_data_start_rgt: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Starting Reference Groundtrack 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. source: Derived valid_min: 1 valid_max: 1387 origname: start_rgt fullnamepath: /ancillary_data/start_rgt |
| ancillary_data_end_gpssow: | Array of 64 bit Reals [FakeDim0 = 0..0] units: seconds contentType: auxiliaryInformation long_name: Ending GPS SOW of Granule (Actual) description: GPS seconds-of-week of the last data point in the granule. source: Derived origname: end_gpssow fullnamepath: /ancillary_data/end_gpssow |
| ancillary_data_qa_at_interval: | Array of 64 bit Reals [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: QA Along-Track Interval description: Statistics time interval for along-track QA data. source: control origname: qa_at_interval fullnamepath: /ancillary_data/qa_at_interval |
| ancillary_data_start_region: | Array of 32 bit Integers [FakeDim0 = 0..0] units: 1 contentType: auxiliaryInformation long_name: Starting Region 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. source: Derived origname: start_region fullnamepath: /ancillary_data/start_region |
| ancillary_data_start_gpsweek: | Array of 32 bit Integers [FakeDim0 = 0..0] units: weeks from 1980-01-06 contentType: auxiliaryInformation long_name: Start GPSWeek of Granule (Actual) description: GPS week number of the first data point in the granule. source: Derived origname: start_gpsweek fullnamepath: /ancillary_data/start_gpsweek |
| gt3r_signal_photons_classed_pc_flag: | Array of 16 bit Integers [gt3r_signal_photons_delta_time = 0..946496] units: 1 long_name: photon land atbd classification description: Land Vegetation ATBD classification flag for each photon as either noise, ground, canopy, and top of canopy. 0 = noise, 1 = ground, 2 = canopy, or 3 = top of canopy. source: Land ATBD section 4.10 flag_meanings: noise ground canopy top_of_canopy flag_values: 0, 1, 2, 3 origname: classed_pc_flag fullnamepath: /gt3r/signal_photons/classed_pc_flag coordinates: gt3r_signal_photons_delta_time |
| gt3r_signal_photons_classed_pc_indx: | Array of 32 bit Integers [gt3r_signal_photons_delta_time = 0..946496] units: 1 contentType: referenceInformation long_name: indicies of classed photons description: Index (1-based) of the ATL08 classified signal photon from the start of the ATL03 geolocation segment specified on the ATL08 product at the photon rate in the corresponding parameter, ph_segment_id. This index traces back to specific photon within a 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: classed_pc_indx fullnamepath: /gt3r/signal_photons/classed_pc_indx coordinates: gt3r_signal_photons_delta_time |
| gt3r_signal_photons_d_flag: | Array of 16 bit Integers [gt3r_signal_photons_delta_time = 0..946496] units: 1 long_name: dragann flag description: Flag indicating the labeling of DRAGANN noise filtering for a given photon. source: Land ATBD section 2.3.5 flag_meanings: noise signal flag_values: 0, 1 origname: d_flag fullnamepath: /gt3r/signal_photons/d_flag coordinates: gt3r_signal_photons_delta_time |
| gt3r_signal_photons_ph_segment_id: | Array of 32 bit Integers [gt3r_signal_photons_delta_time = 0..946496] units: 1 contentType: referenceInformation long_name: segment id of photon description: Segment ID of photons tracing back to specific 20m segment_id on ATL03. The unique identifier for tracing each ATL08 signal photon to the photon on ATL03 is the segment_id, orbit, and classed_pc_indx. The unique identifier for tracing each ATL08 signal photon to the corresponding photon record on ATL03 is the segment_id, orbit, cycle, and classed_pc_indx. Orbit and cycle intervals for the granule are found in the /ancillary_data. The timestamp of each orbit transition is found in the /orbit_info group. source: Retained from prior a_alt_science_ph packet origname: ph_segment_id fullnamepath: /gt3r/signal_photons/ph_segment_id coordinates: gt3r_signal_photons_delta_time |
| gt3r_land_segments_segment_watermask: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 255 units: 1 long_name: segment watermask description: Water mask(i.e. flag) indicating inland water as referenced from the Global Raster Water Mask(ANC33) at 250 m spatial resolution. source: ATBD section 2.4.15 flag_meanings: no_water water flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: segment_watermask fullnamepath: /gt3r/land_segments/segment_watermask coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_delta_time_end: | Array of 64 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time end description: Time of the last photon contained within the data segment, in 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_end fullnamepath: /gt3r/land_segments/delta_time_end coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_rgt: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 contentType: referenceInformation long_name: reference ground track 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 GT3 and GT4. During slews or off-pointing, it is possible that ground tracks may intersect the RGT. The ICESat-2 mission has 1387 RGTs. source: Operations valid_min: 1 valid_max: 1387 origname: rgt fullnamepath: /gt3r/land_segments/rgt coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_dem_flag: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] contentType: referenceInformation long_name: dem source flag description: Indicates source of the DEM height. Values: 0=None, 1=GIMP, 2=GMTED, 3=MSS, 4=Antarctic. source: Atmosphere ATBD flag_meanings: none gimp gmted mss antarctic flag_values: 0, 1, 2, 3, 4 valid_min: 0 valid_max: 4 _FillValue: 127 units: 1 origname: dem_flag fullnamepath: /gt3r/land_segments/dem_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_msw_flag: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 127 units: 1 long_name: multiple scattering warning flag description: Multiple scattering warning flag has values from 0 to 5. 0=no_scattering, 1=clouds at <1km, 2=clouds at 1-3km, 3=clouds at >3km, 4=blowing snow at <0.5, 5=blowing snow at >=0.5km. source: ATL09 flag_meanings: no_scattering clouds_at_<1km, clouds_at_1-3km clouds_at_>3km, blowing_snow_at_<0.5 blowing snow_at_>=0.5km flag_values: 0, 1, 2, 3, 4, 5 origname: msw_flag fullnamepath: /gt3r/land_segments/msw_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_snr: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] long_name: signal to noise ratio description: The signal to noise ratio of geolocated photons as determined by the ratio of the superset of ATL03 signal and DRAGANN found signal photons used for processing the ATL08 segments to the background photons (i.e. noise) within the same ATL08 segments. source: ATBD section 2.5.14 _FillValue: 3.402823466e+38 units: 1 origname: snr fullnamepath: /gt3r/land_segments/snr coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: height canopy description: 98% height of all the individual canopy relative heights for the segment above the estimated terrain surface. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_canopy fullnamepath: /gt3r/land_segments/canopy/h_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_canopy_rh_conf: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 contentType: modelResult long_name: canopy relative height confidence description: Canopy relative height confidence flag based on percentage of ground and canopy photons within a segment: 0 (<5% canopy), 1 (>5% canopy, <5% ground), 2 (>5% canopy, >5% ground). source: Land/Veg ATBD 13March2019, Section 2.2.21 flag_meanings: <5%_canopy >=5%_canopy_<5%_ground >=5%_canopy_>=5%_ground flag_values: 0, 1, 2 valid_min: 0 valid_max: 2 origname: canopy_rh_conf fullnamepath: /gt3r/land_segments/canopy/canopy_rh_conf coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_median_canopy_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment median canopy height description: The median of individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.6 origname: h_median_canopy_abs fullnamepath: /gt3r/land_segments/canopy/h_median_canopy_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_min_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: minimum canopy height description: The minimum of relative individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 2.2.10 origname: h_min_canopy fullnamepath: /gt3r/land_segments/canopy/h_min_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_mean_canopy_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: absolute mean canopy height description: Mean of the individual absolute canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.4 origname: h_mean_canopy_abs fullnamepath: /gt3r/land_segments/canopy/h_mean_canopy_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_median_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: median canopy height description: The median of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. This parameter should be equivalent to RH50 reported in the literature. source: Land ATBD section 2.2.8 origname: h_median_canopy fullnamepath: /gt3r/land_segments/canopy/h_median_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_canopy_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: absolute segment canopy height description: The 98% height of all the absolute individual canopy heights referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.2 origname: h_canopy_abs fullnamepath: /gt3r/land_segments/canopy/h_canopy_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_toc_roughness: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: top of canopy roughness description: Standard deviation of the relative heights of all photons classified as top of canopy within the segment source: Land ATBD section 4.12 origname: toc_roughness fullnamepath: /gt3r/land_segments/canopy/toc_roughness coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_min_canopy_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: absolute minimum canopy height description: The minimum of absolute individual canopy heights within segment referenced above the WGS84 Ellipsoid. source: Land ATBD section 2.2.9 origname: h_min_canopy_abs fullnamepath: /gt3r/land_segments/canopy/h_min_canopy_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_dif_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: canopy diff to median height description: Difference between h_canopy and h_median_canopy source: Land ATBD section 4.12 origname: h_dif_canopy fullnamepath: /gt3r/land_segments/canopy/h_dif_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_canopy_quad: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] long_name: canopy quadratic mean description: The quadratic mean height of individual classified relative canopy photon heights above the estimated terrain surface. source: Land ATBD section 4.12 _FillValue: 3.402823466e+38 units: meters origname: h_canopy_quad fullnamepath: /gt3r/land_segments/canopy/h_canopy_quad coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_n_ca_photons: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: number canopy photons description: The number of photons classified as canopy within the segment. source: Land ATBD section 4.12 origname: n_ca_photons fullnamepath: /gt3r/land_segments/canopy/n_ca_photons coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_centroid_height: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: centroid height description: Optical centroid of all photons classified as either canopy or ground points within the segment. The heights used in this calculation are absolute heights above the reference ellipsoid. This parameter is equivalent to the centroid height produced ICESat GLA14. source: Land ATBD section 2.2.22 origname: centroid_height fullnamepath: /gt3r/land_segments/canopy/centroid_height coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_canopy_h_metrics_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy absolute height metrics description: Height metrics based on the cumulative distribution of absolute canopy heights above the WGS84 Ellipsoid. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics_abs fullnamepath: /gt3r/land_segments/canopy/canopy_h_metrics_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_landsat_perc: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 long_name: landsat percentage canopy description: Average percentage value of the valid (value <= 100) Landsat Tree Cover Continuous Fields product for each 100 m segment source: Land ATBD section 2.2.24 origname: landsat_perc fullnamepath: /gt3r/land_segments/canopy/landsat_perc coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_mean_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: mean canopy height description: Mean of individual relative canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. source: Land ATBD section 4.12 origname: h_mean_canopy fullnamepath: /gt3r/land_segments/canopy/h_mean_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_canopy_h_metrics: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885][ds_metrics = 0..8] _FillValue: 3.402823466e+38 units: meters long_name: canopy height metrics description: Height metrics based on the cumulative distribution of relative canopy heights above the interpolated ground surface. The height metrics are calculated at the following percentiles: 25,50,60,70,75,80,85,90,95%. source: Land ATBD section 2.2.3 origname: canopy_h_metrics fullnamepath: /gt3r/land_segments/canopy/canopy_h_metrics coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_n_toc_photons: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: number top of canopy photons description: The number of photons classified as top of canopy within the segment. source: Land ATBD section 4.12 origname: n_toc_photons fullnamepath: /gt3r/land_segments/canopy/n_toc_photons coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_canopy_flag: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 2147483647 units: 1 long_name: canopy flag description: Flag indicating that canopy was detected using the Landsat Tree Cover Continuous Fields data product. If percent of canopy cover along the L-km segment is greater than 5%, then canopy is assumed to be present; else, no canopy is assumed present. source: Land ATBD section 2.2.22 flag_meanings: no_canopy_present canopy_present flag_values: 0, 1 origname: canopy_flag fullnamepath: /gt3r/land_segments/canopy/canopy_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_landsat_flag: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 2147483647 units: 1 long_name: landsat flag description: Flag indicating that more than 50% of the Landsat Continuous Cover product have values > 100 for the L-Km segment. Canopy is assumed present along the L-km segment if landsat_flag is 1. source: Land ATBD section 2.2.25 flag_meanings: canopy_not_assumed_present canopy_assumed_present flag_values: 0, 1 origname: landsat_flag fullnamepath: /gt3r/land_segments/canopy/landsat_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_max_canopy_abs: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: absolute maximum canopy height description: Maximum of individual absolute canopy heights within segment referenced above the WGS84 ellipsoid. source: Land ATBD section 2.2.11 origname: h_max_canopy_abs fullnamepath: /gt3r/land_segments/canopy/h_max_canopy_abs coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_canopy_uncertainty: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: segment canopy height uncertainty description: Uncertainty of the relative canopy heights for the segment. Incorporates all systematic uncertainties as well as uncertainty from errors of identified photons. See section 1 and equations 1.4 and 1.5 in the Land ATBD source: Land ATBD section 1.5 origname: h_canopy_uncertainty fullnamepath: /gt3r/land_segments/canopy/h_canopy_uncertainty coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_canopy_openness: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 long_name: canopy openness description: Standard Deviation of all photons classified as canopy photons within the segment to provide inference of canopy openness. source: Land ATBD section 4.12 origname: canopy_openness fullnamepath: /gt3r/land_segments/canopy/canopy_openness coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_canopy_h_max_canopy: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: maximum canopy height description: Relative maximum of individual canopy heights within segment. Relative canopy heights have been computed by differencing the canopy photon height from the estimated terrain surface. Should be equivalent to RH100 metric reported in the literature. source: Land ATBD section 2.2.12 origname: h_max_canopy fullnamepath: /gt3r/land_segments/canopy/h_max_canopy coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_sigma_across: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas y description: Total cross-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_across. Sigma_atlas_y is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_across fullnamepath: /gt3r/land_segments/sigma_across coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_uncertainty: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: uncertainty of h_te_mean description: Uncertainty of the mean terrain height for the segment. This uncertainty incorporates all systematic uncertainties(e.g. timing orbits, geolocation,etc.) as well as uncertainty from errors of identified photons. This parameter is described in section 1, equation 1.4 source: Land ATBD section 4.11 origname: h_te_uncertainty fullnamepath: /gt3r/land_segments/terrain/h_te_uncertainty coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_mean: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: mean terrain height description: The mean of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mean fullnamepath: /gt3r/land_segments/terrain/h_te_mean coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_min: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: minimum terrain height description: The minimum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_min fullnamepath: /gt3r/land_segments/terrain/h_te_min coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_interp: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: interpolated terrain surface height description: Interpolated terrain surface height above the WGS84 Ellipsoid at the midpoint of the segment. source: Land ATBD section 4.9 origname: h_te_interp fullnamepath: /gt3r/land_segments/terrain/h_te_interp coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_max: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: maximum terrain height description: The maximum of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_max fullnamepath: /gt3r/land_segments/terrain/h_te_max coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_skew: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: skew of terrain heights description: The skewness of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_skew fullnamepath: /gt3r/land_segments/terrain/h_te_skew coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_median: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: median terrain height description: The median of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_median fullnamepath: /gt3r/land_segments/terrain/h_te_median coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_best_fit: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: segment terrain height best fit description: The best fit terrain elevation at the the mid-point location of each 100m segment. The mid-segment terrain elevation is determined by selecting the best of three fits- linear, 3rd order and 4th order polynomials - to the terrain photons and interpolating the elevation at the mid-point location of the 100 m segment. For the linear fit, a slope correction and weighting is applied to each ground photon based on the distance to the slope height at the center of the segment. source: Land ATBD section 2.1.15 origname: h_te_best_fit fullnamepath: /gt3r/land_segments/terrain/h_te_best_fit coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_std: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] long_name: segment terrain roughness description: The standard deviation of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 _FillValue: 3.402823466e+38 units: meters origname: h_te_std fullnamepath: /gt3r/land_segments/terrain/h_te_std coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_terrain_slope: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 long_name: segment terrain slope description: The along-track slope of terrain, within each segment;computed by a linear fit of terrain classified photons. Slope is in units of delta height over delta along track distance. source: Land ATBD section 4.11 origname: terrain_slope fullnamepath: /gt3r/land_segments/terrain/terrain_slope coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_n_te_photons: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: number of ground photons description: The number of the photons classified as terrain within the segment. source: Land ATBD section 4.11 origname: n_te_photons fullnamepath: /gt3r/land_segments/terrain/n_te_photons coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_h_te_mode: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: mode of terrain heights description: The mode of the photon heights above the WGS84 Ellipsoid, classified as terrain within the segment. source: Land ATBD section 4.11 origname: h_te_mode fullnamepath: /gt3r/land_segments/terrain/h_te_mode coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_segment_snowcover: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 127 units: 1 long_name: segment snowcover description: Daily snow/ice cover from ATL09 at the 25 Hz rate(275m) indicating likely presence of snow and ice within each segment. 0=ice free water; 1=snow free land; 2=snow; 3=ice. source: ATBD section 4.2.16 flag_meanings: ice_free_water snow_free_land snow ice flag_values: 0, 1, 2, 3 valid_min: 0 valid_max: 3 origname: segment_snowcover fullnamepath: /gt3r/land_segments/segment_snowcover coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_beam_azimuth: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam azimuth description: Azimuth(in radians) 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. source: ATL03 origname: beam_azimuth fullnamepath: /gt3r/land_segments/beam_azimuth coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_solar_azimuth: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: degrees_east contentType: referenceInformation long_name: solar azimuth description: The direction, eastwards from north, of the sun vector as seen by an observer at the laser ground spot. source: ATL03g ATBD origname: solar_azimuth fullnamepath: /gt3r/land_segments/solar_azimuth coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_psf_flag: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 contentType: referenceInformation long_name: point spread function flag description: Flag is set to 1 if the point spread function (computed as sigma_atlas_land) has exceeded the threshold (1 m) source: Land/Veg ATBD flag_meanings: below_threshold above_threshold flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: psf_flag fullnamepath: /gt3r/land_segments/psf_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_longitude: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: degrees long_name: longitude standard_name: longitude description: Longitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -180.0000000 valid_max: 180.0000000 origname: longitude fullnamepath: /gt3r/land_segments/longitude coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude |
| gt3r_land_segments_latitude: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: degrees long_name: latitude standard_name: latitude description: Latitude of the center-most signal photon within each segment. source: Land ATBD section 2.4 valid_min: -90.00000000 valid_max: 90.00000000 origname: latitude fullnamepath: /gt3r/land_segments/latitude coordinates: gt3r_land_segments_delta_time gt3r_land_segments_longitude |
| gt3r_land_segments_segment_id_end: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 contentType: referenceInformation long_name: end geolocation segment bin description: Geolocation segment number of the last photon in the land segment. source: ATL03 origname: segment_id_end fullnamepath: /gt3r/land_segments/segment_id_end coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_surf_type: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885][ds_surf_type = 0..4] units: 1 contentType: referenceInformation long_name: surface type 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. source: ATL03 ATBD, Section 4 flag_meanings: not_type is_type flag_values: 0, 1 valid_min: 0 valid_max: 1 origname: surf_type fullnamepath: /gt3r/land_segments/surf_type coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_segment_landcover: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 255 units: 1 long_name: segment landcover description: IGBP Land Cover Surface type classification as reference from MODIS Land Cover(ANC18) at the 0.5 arcsecond resolution. source: ATBD section 2.4.14 flag_meanings: Water Evergreen_Needleleaf_Forest Evergreen_Broadleaf_Forest Deciduous_Needleleaf_Forest Deciduous_Broadleaf_Forest Mixed_Forest Closed_Shrublands Open_Shrubland Woody_Savanna Savanna Grassland Wetland Croplands Urban Crop_Mosaic Permanent_Snow Barren flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 valid_min: 0 valid_max: 16 origname: segment_landcover fullnamepath: /gt3r/land_segments/segment_landcover coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_ph_removal_flag: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: ph removal flag description: Flag indicating more than ph_removal_percent_limit (default 50.0) removed from land segment due to failing QA tests source: ATBD section 4.13 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: ph_removal_flag fullnamepath: /gt3r/land_segments/ph_removal_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_asr: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 long_name: apparent surface reflectance description: Apparent surface reflectance source: ATL09 origname: asr fullnamepath: /gt3r/land_segments/asr coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_sigma_atlas_land: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas land description: Total vertical geolocation error due to ranging and local surface slope. The parameter is computed for ATL08 as described in equation 1.2. source: Land ATBD section 2.5.13 origname: sigma_atlas_land fullnamepath: /gt3r/land_segments/sigma_atlas_land coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_segment_id_beg: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 contentType: referenceInformation long_name: begin geolocation segment bin description: Geolocation segment number of the first photon in the land segment. source: ATL03 origname: segment_id_beg fullnamepath: /gt3r/land_segments/segment_id_beg coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_sigma_along: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas x description: Total along-track uncertainty due to PPD and POD knowledge. Read from ATL03 product gtx/geolocation/sigma_along. Sigma_atlas_x is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_along fullnamepath: /gt3r/land_segments/sigma_along coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_dem_h: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters contentType: referenceInformation long_name: dem height description: Best available DEM (in priority of GIMP/ANTARCTIC/GMTED/MSS) value at the geolocation point. Height is in meters above the WGS84 Ellipsoid. source: GIMP, GMTED,MSS origname: dem_h fullnamepath: /gt3r/land_segments/dem_h coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_cloud_flag_asr: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 127 units: 1 long_name: cloud flag from asr description: Cloud confidence flag from ATL09. Flag indicates potential clear skies from ATL09. Cloud Product Flags: 0 = High confidence clear skies, 1 = Medium confidence clear skies, 2 = Low confidence clear skies, 3 = Low confidence cloudy skies, 4 = Medium confidence cloudy skies, 5 = High confidence cloudy skies source: ATL09 flag_meanings: clear_high_confidence clear_medium_confidence clear_low_confidence cloudy_low_confidence cloudy_medium_confidence cloudy_high_confidence flag_values: 0, 1, 2, 3, 4, 5 origname: cloud_flag_asr fullnamepath: /gt3r/land_segments/cloud_flag_asr coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_beam_coelev: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: beam co-elevation description: Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot. source: ATL03 origname: beam_coelev fullnamepath: /gt3r/land_segments/beam_coelev coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_sigma_topo: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: sigma atlas topo description: Total uncertainty that include sigma_h plus geolocation uncertainty due to local slope (equation 1.3). The local slope is multiplied by the geolocation uncertainty factor. This will be used to determine the total vertical geolocation error due to ranging and local slope. source: Land ATBD section 2.5.12 origname: sigma_topo fullnamepath: /gt3r/land_segments/sigma_topo coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_night_flag: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 2147483647 units: 1 long_name: night flag description: Flag indicating the data were acquired in night conditions: 0=day, 1=night. Flag is derived from solar elevation at the geolocated segment. IF solar elevation is above threshold it is day, if not then it is night. Threshold is set in atlas_l3a_const_mod. source: Land ATBD section 2.4.8 flag_meanings: day night flag_values: 0, 1 origname: night_flag fullnamepath: /gt3r/land_segments/night_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_delta_time_beg: | Array of 64 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: seconds since 2018-01-01 contentType: referenceInformation long_name: delta time begin description: Time of the first photon contained within the data segment, 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. source: Derived (gps_seconds-gps_sec_offset) origname: delta_time_beg fullnamepath: /gt3r/land_segments/delta_time_beg coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_sigma_h: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: 1 contentType: referenceInformation long_name: height uncertainty description: Estimated uncertainty for the reference photon bounce point ellipsoid height: 1- sigma (m) provided at the geolocation segment rate on ATL03. Sigma_h is reported on ATL08 as the uncertainty of the center-most reference photon of the 100m ATL08 segment. source: ATL03 origname: sigma_h fullnamepath: /gt3r/land_segments/sigma_h coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_last_seg_extend: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: kilometers long_name: last segment extended standard_name: last_seg_extend description: The distance (km) that the last ATL08 processing segment in a file is either extended or overlapped with the previous ATL08 processing segment. source: Land ATBD 13March2019, Section 2.4.20 origname: last_seg_extend fullnamepath: /gt3r/land_segments/last_seg_extend coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_atlas_pa: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: radians contentType: referenceInformation long_name: atlas pointing angle description: Off nadir pointing angle (in radians) of the satellite to increase spatial sampling in the non-polar regions. ATLAS_PA =90degs-beam_coelev. source: ATL03 origname: atlas_pa fullnamepath: /gt3r/land_segments/atlas_pa coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_segment_id: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: segment index description: 20m segment_id for the center-most photon of the 100 meter short segment. Unique counter is the orbit, region, and segment_id. source: Derived origname: segment_id fullnamepath: /gt3r/land_segments/segment_id coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_solar_elevation: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: degrees contentType: referenceInformation long_name: solar elevation description: Solar Angle above or below the plane tangent to the ellipsoid surface at the laser spot. Positive values mean the sun is above the horizon, while negative values mean it is below the horizon. The effect of atmospheric refraction is not included. This is a low precision value, with approximately TBD degree accuracy. source: ATL03g ATBD origname: solar_elevation fullnamepath: /gt3r/land_segments/solar_elevation coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_n_seg_ph: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: number of photons description: Number of photons within each land segment. source: Derived origname: n_seg_ph fullnamepath: /gt3r/land_segments/n_seg_ph coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_terrain_flg: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 2147483647 units: 1 long_name: terrain flag description: Terrain flag quality check to indicate a deviation above a threshold from the reference DEM height reported on the product. source: Land ATBD section 2.4.8 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: terrain_flg fullnamepath: /gt3r/land_segments/terrain_flg coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_urban_flag: | Array of 32 bit Integers [gt3r_land_segments_delta_time = 0..3885] _FillValue: 2147483647 units: 1 long_name: segment urban flag description: The urban flag indicates that a segment is likely located over an urban area. source: Land ATBD section 2.4.17 flag_meanings: not_urban urban flag_values: 0, 1 origname: urban_flag fullnamepath: /gt3r/land_segments/urban_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_dem_removal_flag: | Array of 16 bit Integers [gt3r_land_segments_delta_time = 0..3885] units: 1 long_name: dem removal flag description: Flag indicating more than dem_removal_percent_limit (default 20.0) removed from land segment due to failing DEM-QA tests source: ATBD section 2.4.11 flag_meanings: below_threshold above_threshold flag_values: 0, 1 origname: dem_removal_flag fullnamepath: /gt3r/land_segments/dem_removal_flag coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| gt3r_land_segments_h_dif_ref: | Array of 32 bit Reals [gt3r_land_segments_delta_time = 0..3885] _FillValue: 3.402823466e+38 units: meters long_name: h dif from reference description: Difference between h_te_median and ref_DEM source: Land ATBD section 2.4 origname: h_dif_ref fullnamepath: /gt3r/land_segments/h_dif_ref coordinates: gt3r_land_segments_delta_time gt3r_land_segments_latitude gt3r_land_segments_longitude |
| ds_metrics: | Array of 16 bit Integers [ds_metrics = 0..8] units: 1 contentType: referenceInformation long_name: Metrics description: Dimension scale for metrics. flag_meanings: metrics1 metrics2 metrics3 metrics4 metrics5 metrics6 metrics7 metrics8 metrics9 flag_values: 1, 2, 3, 4, 5, 6, 7, 8, 9 valid_min: 1 valid_max: 4 origname: ds_metrics fullnamepath: /ds_metrics |
| ds_surf_type: | Array of 32 bit Integers [ds_surf_type = 0..4] units: 1 contentType: auxiliaryInformation long_name: Surface Type Dimension Scale 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 flag_meanings: land ocean seaice landice inland_water flag_values: 1, 2, 3, 4, 5 valid_min: 1 valid_max: 5 origname: ds_surf_type fullnamepath: /ds_surf_type |
| gt1l_land_segments_delta_time: | Array of 64 bit Reals [gt1l_land_segments_delta_time = 0..4981] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt1l/land_segments/delta_time |
| gt1l_signal_photons_delta_time: | Array of 64 bit Reals [gt1l_signal_photons_delta_time = 0..3446216] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt1l/signal_photons/delta_time |
| gt1r_land_segments_delta_time: | Array of 64 bit Reals [gt1r_land_segments_delta_time = 0..3917] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt1r/land_segments/delta_time |
| gt1r_signal_photons_delta_time: | Array of 64 bit Reals [gt1r_signal_photons_delta_time = 0..987773] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt1r/signal_photons/delta_time |
| gt2l_land_segments_delta_time: | Array of 64 bit Reals [gt2l_land_segments_delta_time = 0..4623] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt2l/land_segments/delta_time |
| gt2l_signal_photons_delta_time: | Array of 64 bit Reals [gt2l_signal_photons_delta_time = 0..2717621] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt2l/signal_photons/delta_time |
| gt2r_land_segments_delta_time: | Array of 64 bit Reals [gt2r_land_segments_delta_time = 0..3837] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt2r/land_segments/delta_time |
| gt2r_signal_photons_delta_time: | Array of 64 bit Reals [gt2r_signal_photons_delta_time = 0..972261] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt2r/signal_photons/delta_time |
| gt3l_land_segments_delta_time: | Array of 64 bit Reals [gt3l_land_segments_delta_time = 0..4926] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt3l/land_segments/delta_time |
| gt3l_signal_photons_delta_time: | Array of 64 bit Reals [gt3l_signal_photons_delta_time = 0..3319973] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt3l/signal_photons/delta_time |
| gt3r_land_segments_delta_time: | Array of 64 bit Reals [gt3r_land_segments_delta_time = 0..3885] units: seconds since 2018-01-01 long_name: mean_pass_time standard_name: time description: Mean time for the segment in 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. source: Land ATBD section 2.4 coordinates: latitude longitude origname: delta_time fullnamepath: /gt3r/land_segments/delta_time |
| gt3r_signal_photons_delta_time: | Array of 64 bit Reals [gt3r_signal_photons_delta_time = 0..946496] units: seconds since 2018-01-01 long_name: delta time standard_name: time 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. source: ATL03 origname: delta_time fullnamepath: /gt3r/signal_photons/delta_time |
| orbit_info_crossing_time: | Array of 64 bit Reals [orbit_info_crossing_time = 0..0] units: seconds since 2018-01-01 contentType: referenceInformation long_name: Ascending Node Crossing Time standard_name: time 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. source: POD/PPD origname: crossing_time fullnamepath: /orbit_info/crossing_time |
| orbit_info_sc_orient_time: | Array of 64 bit Reals [orbit_info_sc_orient_time = 0..0] units: seconds since 2018-01-01 contentType: referenceInformation long_name: Time of Last Spacecraft Orientation Change standard_name: time 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. source: POD/PPD origname: sc_orient_time fullnamepath: /orbit_info/sc_orient_time |
| FakeDim0: | Array of 32 bit Integers [FakeDim0 = 0..0] units: level |