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Data Set ID: 

ATLAS/ICESat-2 L3A Along Track Inland Surface Water Data, Version 4

This data set (ATL13) contains along-track surface water products for inland water bodies. Inland water bodies include lakes, reservoirs, rivers, bays, estuaries and a 7km near-shore buffer. Principal data products include the along-track water surface height and standard deviation, subsurface signal (532 nm) attenuation, significant wave height, wind speed, and coarse depth to bottom topography (where data permit).

There is a more recent version of these data.

Version Summary: 

Changes for this version include:

  • Implemented retention of unused photons associated with the same geolocation segment pulse ID and major frame ID (ph_id_pulse, pce_mframe_cnt) across ATL13 segments/transects.
  • Implemented exclusion of TEP photon events when forming ATL13 short segments.
  • Implemented computation of water surface spectral moments and spectral width. The spectral width flag (qf_spec_width) is now reported on the ATL13 product.
  • Fixed errors related to the identification of photons necessary to define valid crests and upcrossings for the computation of the spectral width parameter and electromagnetic bias (segment_bias_em).
  • Updated source code for a sign change to compute electromagnetic bias (segment_bias_em) as a positive expression.
  • Filtered geolocation segments whose composite POD/PPD flag is non-zero, invalidating possibly degraded geolocation solutions.
  • Updated weak beam interpolation of ATL09 strong beam atmospheric profile source data (e.g. cloud_flag_atm) to be aligned by along-track segment (segment_id) and not time.
  • Added short segment fractions of near and full saturation, computed from a weighted average of nearly and fully saturated fractions of pulses within ATL03 geo-segments overlapping the segment.
  • Added DEM height & source at the short segment rate, based on DEM heights and sources of ATL03 reference photons of all geolocation segments overlapping the short segment.
  • The ATL03 EGM2008 geoid is now reported in the tide free system. Implemented updates to WGS-84 ellipsoid photon heights to re-reference the mean tide system geoid when forming orthometric height, using geoid_free2mean.
  • Implemented computation of height adjustment to be applied to the apparent surface height to account for deconvolution analysis, and added a flag representing the range of long segment height adjustment values (qf_ht_adj).
  • Both the first photon bias correction (segment_fpb_correction) and mean height adjustment estimated from deconvolution are now applied to the observed apparent surface height (segment_apparent_height) when computing orthometric heights and heights referenced to the WGS-84 ellipsoid (ht_ortho & ht_water_surf).
  • Implemented updates to ATL13 short segment along-track water body surface slope (segment_slope_trk_bdy) to include spacecraft velocity in its derivation.
  • Added additional tiers to the flag that indicates the range of long segment lengths (qf_lseg_length).
  • Implemented exclusion of very long (L_sub_ID) segments associated with insufficient photon counts within the range of subsurface fit from contributing to the exponential fit to the observed histogram.
  • Made anomalous short-segment information available in a separate subgroup, anom_ssegs, populated with output parameters such as water body reference ID, standard deviation of signal photon heights per segment and coarse water height (atl13refid, anom_sseg_stdev & coarse_transect_ht) for segments deemed anomalous within each body transect.
  • Implemented ingestion of ATL03 quality_ph (at photon rate) and computation of short segment photon counts designated at each quality level (as described by elements of the dimension scale vector /ds_sseg_quality) as a rank 2 array for both anomalous & non-anomalous segments (segment_quality & anom_sseg_quality).
  • The short segment anomaly testing is now inclusive of all anomaly tests. Within the anom_ssegs subgroup, the trigger flag anom_sseg_trigger_flag has been implemented as a rank 2 array, where the magnitude of each row element indicates result of anomaly testing from a specific cause for a given segment, as described by elements of the dimension scale vector /ds_anom_trigger.
  • Added anomalous short segment averaged coordinates and length based on endpoint locations with the anom_ssegs subgroup.
Data Format(s):
  • HDF5
Spatial Coverage:
N: 90, 
S: -90, 
E: 180, 
W: -180
Spatial Resolution:
  • Varies
Temporal Coverage:
  • 13 October 2018 to 15 July 2021
Temporal Resolution91 dayMetadata XML:View Metadata Record
Data Contributor(s):Michael Jasinski, Jeremy Stoll, David Hancock, John Robbins, Jyothi Nattala, et al

Geographic Coverage

No access options.

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Jasinski, M. F., J. D. Stoll, D. Hancock, J. Robbins, J. Nattala, J. Morison, B. M. Jones, M. E. Ondrusek, T. M. Pavelsky, C. Parrish, and the ICESat-2 Science Team. 2021. ATLAS/ICESat-2 L3A Along Track Inland Surface Water Data, Version 4. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].

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