ATLAS/ICESat-2 L3A Land Ice Height, Version 3
As of 25 January 2022, this data set is retired and no longer available for download. Per our agreement with the data provider, NSIDC only archives the most recent version of each of the ICESat-2 standard products and the version that preceded it. The most recent version is available from https://nsidc.org/data/icesat-2/data-sets.
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This data set (ATL06) provides geolocated, land-ice surface heights (above the WGS 84 ellipsoid, ITRF2014 reference frame), plus ancillary parameters that can be used to interpret and assess the quality of the height estimates. The data were acquired by the Advanced Topographic Laser Altimeter System (ATLAS) instrument on board the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) observatory.
There is a more recent version of these data.
Changes for this version include:
- ATL09 pass-through data (cloud flag parameters) are now being written to ATL06 (gt[x]/land_ice_segments/geophysical/layer_flag). Note that if two flags intersect an ATL06 segment, the higher flag value is used. The layer_flag parameter is important for predicting forward scattering.
- The large DEMs previously used by ATL06 are no longer required inputs. If they are provided in the processing control file, the values are queried as in previous releases; if the DEMs are not provided in the control file, DEM values from ATL03 are used.
- Molecular transmission used to compute effective background is now being read from ATL09. Prior versions used a default value.
- Added radial orbit error as gt[x]/land_ice_segments/ground_track/sigma_geo_r (parameter sigma_h from ATL03).
- ATL03 data flagged with non-zero values in podppd_flag are no longer processed for ATL06. This criteria ensures that land ice data are created only from ATL03 data that are accurately geolocated and eliminates most ATL06 data that in prior versions contained substantial correlated errors.
- Changed the residual histograms to range from -50m to +50m with varying bin sizes. Residual histogram bins that are not fully encompassed by at least one of the two possible telemetry band range windows are marked as invalid. These larger histograms encompass the full potential vertical range of forward-scattering returns below the surface and allow sampling of backscatter from blowing snow above the surface.
- Corrected the long names for sigma_geo_at and sigma_geo_xt in the ATL06 file metadata.
- Residual histograms are centered on h_mean instead of h_li. Centering the histogram on the mean, rather than the median, yields a better representation of the segment-to-segment statistics for the residuals.
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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.
Smith, B., H. A. Fricker, A. Gardner, M. R. Siegfried, S. Adusumilli, B. M. Csathó, N. Holschuh, J. Nilsson, F. S. Paolo, and the ICESat-2 Science Team. 2020. ATLAS/ICESat-2 L3A Land Ice Height, Version 3. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/ATLAS/ATL06.003. [Date Accessed].