ATLAS/ICESat-2 L3A Sea Ice Height, Version 7
Data set id:
ATL07
DOI: 10.5067/ATLAS/ATL07.007
This is the most recent version of these data.
Version Summary
Version Summary
-Added starting along-track distance of sea-ice segment to main data group. Average along-track distance remains on product. The entire span of an ATL07 segment can be found using starting along-track distance and segment length.
-Introduced lognormal distributions to be used as alternate expected waveform table. If a sea ice height return does not provide a good fit to the standard expected waveform table using Gaussian distributions, re-process the height segment using lognormal expected waveform table. The original results are kept, and the results of the re-processed height segment are stored on new lognormal parameters.
-Implemented the option to process sea ice heights at half-stepping, 10-meter segment lengths. By default, the sea ice heights are constructed at variable-length segments, constructed by aggregating 150 photons. The segment length, and the amount of overlapping, can be modified with the control file (the constant-length segmenting may be run by adding the following override command to the control file: asas.atl07.buffered_segments_flag=1)
-Introduced DDA-Bifurcation algorithm. DDA provides a new surface finding algorithm which provides independently computed heights along with the ATL07 heights. The routine also allows for the bifurcation of the surface to detect and measure potential melt ponds. ATL07 sea ice segments within these potential melt ponds are flagged. These results should be considered experimental as sufficient testing has not been completed.
-Updated algorithm to apply Dynamic Atmosphere Correction (DAC) as a geophysical correction. Static and Dynamic inverted barometer corrections (computed within atlas_l3a_si) were used as geophysical corrections in v5 and v6. DAC is provided on ATL03 and does not need to be computed within atlas_l3a_si. This change introduces product consistency with surface height returns from the ATL12 ocean surface heights product.
-Introduced new fine-tracker algorithm to make it modular and introduce custom data groups to help with data handling and writing. Testing is ongoing with the updated algorithm, so the default algorithm is used by default. The new algorithm may be run by adding the following override command to the control file: asas.atl07.finetrack_flag = 1.
-Introduced lognormal distributions to be used as alternate expected waveform table. If a sea ice height return does not provide a good fit to the standard expected waveform table using Gaussian distributions, re-process the height segment using lognormal expected waveform table. The original results are kept, and the results of the re-processed height segment are stored on new lognormal parameters.
-Implemented the option to process sea ice heights at half-stepping, 10-meter segment lengths. By default, the sea ice heights are constructed at variable-length segments, constructed by aggregating 150 photons. The segment length, and the amount of overlapping, can be modified with the control file (the constant-length segmenting may be run by adding the following override command to the control file: asas.atl07.buffered_segments_flag=1)
-Introduced DDA-Bifurcation algorithm. DDA provides a new surface finding algorithm which provides independently computed heights along with the ATL07 heights. The routine also allows for the bifurcation of the surface to detect and measure potential melt ponds. ATL07 sea ice segments within these potential melt ponds are flagged. These results should be considered experimental as sufficient testing has not been completed.
-Updated algorithm to apply Dynamic Atmosphere Correction (DAC) as a geophysical correction. Static and Dynamic inverted barometer corrections (computed within atlas_l3a_si) were used as geophysical corrections in v5 and v6. DAC is provided on ATL03 and does not need to be computed within atlas_l3a_si. This change introduces product consistency with surface height returns from the ATL12 ocean surface heights product.
-Introduced new fine-tracker algorithm to make it modular and introduce custom data groups to help with data handling and writing. Testing is ongoing with the updated algorithm, so the default algorithm is used by default. The new algorithm may be run by adding the following override command to the control file: asas.atl07.finetrack_flag = 1.
Overview
ATL07 contains along-track sea surface height and sea ice height for segments of variable lengths for all beams as well as fixed 10-meter segments for strong beams. Heights are also computed using the DDA-Bifurcation algorithm for strong beams. The data were acquired by the Advanced Topographic Laser Altimeter System (ATLAS) instrument on board the ICESat-2 observatory.
Parameter(s):
SEA ICE ELEVATION
Platform(s):
ICESat-2
Sensor(s):
ATLAS
Data Format(s):
HDF5
Temporal Coverage:
- 14 October 2018 to present
Temporal Resolution:
- 91 day
Spatial Resolution:
- Not Specified
Spatial Reference System(s):
- WGS 84EPSG:4326
Spatial Coverage:
- N:88S:-88E:180W:-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
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