HR: 0800h
AN: C11B-0417    [Abstracts]
TI: Comparison of ICESat Data With Airborne Laser Altimeter Measurements Over Arctic Sea Ice
AU: * Kurtz, N T
EM: nkurtz1@umbc.edu
AF: University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250,
AU: Markus, T
EM: thorsten.markus@nasa.gov
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771,
AU: Cavalieri, D J
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771,
AU: Krabill, W
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771,
AU: Miller, J
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771,
AU: Sonntag, J
AF: NASA, Goddard Space Flight Center, Greenbelt, MD 20771,
AB: The areal extent of sea ice has been monitored with satellites for nearly three decades, but much less is known about sea ice thickness. The Geoscience Laser Altimeter System (GLAS) on the NASA Ice, Cloud and land Elevation Satellite (ICESat) can monitor the third dimension of the earth, its height, with unprecedented accuracy. Recent studies suggest that the precision of ICESat is sufficient to provide useful information on the thickness of sea ice as well. In order to assess the accuracy of ICESat, we compare the surface elevation and roughness measurements with high-resolution airborne laser altimeter measurements over the Arctic sea ice north of Alaska taken during the March 2006 EOS Aqua Advanced Microwave Scanning Radiometer (AMSR-E) sea ice validation campaign. Comparison of the elevation measurements show that they agree quite well with correlations of around 0.9 for individual shots and a very small maximum bias of 0.5 cm. The differences are found to decrease quite rapidly when applying running means. Comparison of roughness measurements show that there are significant differences between the two data sets with ICESat generally having a higher value, but applying running means to the data significantly improves the correlations to as high as 0.9. Ocean surface elevation estimates are made with the high-resolution airborne laser altimeter data as well as several methods using lower resolution ICESat data for the conversion of elevation measurements into snow-ice freeboard. The relatively large size of the ICESat footprint is shown to introduce a small bias in the use of the lowest levels of the elevation data as sea level, but the average freeboard for the transect shows good agreement.
DE: 0700 CRYOSPHERE (4540)
DE: 0750 Sea ice (4540)
DE: 0758 Remote sensing
DE: 0794 Instruments and techniques
SC: Cryosphere [C]
MN: 2007 Fall Meeting