ATLAS/ICESat-2 L3A Along Track Inland Surface Water Data, Version 4
Data set id:
ATL13
DOI: 10.5067/ATLAS/ATL13.004
There is a more recent version of these data.
Version Summary
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.
Overview
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).
Parameter(s):
ELEVATION
Platform(s):
ICESat-2
Sensor(s):
ATLAS
Data Format(s):
HDF5
Temporal Coverage:
13 October 2018 to 15 July 2021
Temporal Resolution:
- 91 day
Spatial Resolution:
- Not Specified
Spatial Reference System(s):
WGS 84
EPSG:4326
Spatial Coverage:
N:
90
S:
-90
E:
180
W:
-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Data Access & Tools
This data set has been retired. There is a more recent version of these data.
Documentation
User Guide
ATBDs
General Resources
Product Specification Documents
Help Articles
General Questions & FAQs
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