The Geoscience Laser Altimeter System (GLAS) instrument on the Ice, Cloud, and land Elevation Satellite (ICESat) provides global measurements of elevation, and repeats measurements along nearly-identical tracks; its primary mission is to measure changes in ice volume (mass balance) over time. This digital elevation model (DEM) of Antarctica is derived from GLAS/ICESat laser altimetry profile data ... and provides new surface elevation grids of the ice sheets and coastal areas, with greater latitudinal extent and fewer slope-related effects than radar altimetry.
This DEM is generated from the first seven operational periods (from February 2003 through June 2005) of the GLAS instrument. It is provided on polar stereographic grids at 500 m grid spacing. The grid covers all of Antarctica north of 86∞ S. Elevations are reported as centimeters above the datums, relative to both the WGS 84 ellipsoid and the EGM96 geoid, in two separate elevation data files. A data quality map of the interpolation distance is distributed in addition to the elevation data. ENVI header files are also provided.
The data are in 4-byte (long) signed integer binary files (big endian byte order) and are available via FTP.
Slope and elevation accuracy of the DEMs is best near the latitudinal limit of satellite coverage (±86∞), and provides a good representation of the ice sheet and mountain areas (based on comparison with satellite images). DEM accuracy decreases as track spacing between ICESat profiles increases equatorward. ... As a quality and accuracy indicator, the mean distance of all contributing GLAS surface spot data to the grid cell center was recorded in a separate identical grid for each ice sheet. These mean distance files are provided with the elevation data.
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
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Abshire, J., and 8 others. 2005. Geoscience Laser Altimeter System (GLAS) on the ICESat mission: on-orbit measurement performance. Geophysical Research Letters v. 32, L21S02, doi:10.1029/2005GL1024028.
Brenner, A., and 11 others. 2003. Derivation of range and range distributions from laser pulse waveform analysis for surface elevations, roughness, slope, and vegetations ... heights, Algorithm Theoretical Basis Document (ATBD) v.4.1, available at http://www.csr.utexas.edu/glas/atbd.html.
DiMarzio, J. P., A. C. Brenner, and H. J. Zwally. 2004. Comparison of Envisat and ERS radar altimetry for ice –sheet elevation change studies. ESA Envisat Sympsium, Salzburg, Austria, September 9, 2004.
Krabill, W., W. Abdalati, and 7 others. 2002. Aircraft laser altimetry measurement of elevation changes of the Greenland Ice Sheet: technique and accuracy assessment. J. Geodynamics 34, 357-376.
Shuman, C., J. Zwally, B. Schutz, A. Brenner, J. DiMarzio, V. Schuedo, and H. Fricker. 2006. ICESat Antarctic elevation data: preliminary precision and accuracy assessment. Geophysical Research Letters 33, L07501, doi:10.1029/2005GL025227.
Zwally, H. J., A. C. Brenner, J. A. Major, T. V. Martin, and R. A. Bindschadler. 1990. Satellite radar altimetry over ice, Vol. 1. Processing and corrections of Seasat data over Greenland. NASA Reference Publication 1233.