HR: 1330h
AN: C32A-0444    [PDF]
TI: ICESat Calibration-Validation and Mass Balance Studies in Antarctica
AU: * Csatho, B
EM: csatho.1@osu.edu
AF: Byrd Polar Research Center, The Ohio State University, 1090 Carmack Rd., Columbus, OH 43210 United States
AU: Schenk, T
EM: schenk.2@osu.edu
AF: CEEGS, The Ohio State University, 2070 Hitchcock Hall, Columbus, OH 43210 United States
AU: Huh, K
EM: huh.26@osu.edu
AF: Department of Geologic Sciences, The Ohio State University, 125 South Oval Mall, Columbus, OH 43210 United States
AU: van der Veen, C
EM: vanderveen.1@osu.edu
AF: Department of Geologic Sciences, The Ohio State University, 125 South Oval Mall, Columbus, OH 43210 United States
AU: Lee, I
EM: iplee@uos.ac.kr
AF: Dept. of Geoinformatics, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul, 130-743 Korea, Republic of
AU: Spikes, V B
EM: vandy.spikes@maine.edu
AF: University of Maine, Climate Change Institute, 5790 Bryand Global Sciences Center, Room 303, Orono, ME 04469 United States
AU: Krabill, W
EM: krabill@osb.wff.nasa.gov
AF: NASA, Laboratory for Hydrospheric Processes, Wallops Flight Facility, Wallops, VA 23337 United States
AB: To map mass balance changes of major drainage basins over a relatively short period, ICESat is designed to measure surface elevation changes with an accuracy of 1.5 cm/year for spatial averages of measurements over areas of 100 km$^2$. To achieve this accuracy different post-launch calibration-validation (CV) approaches are used to identify and to remove the non-geophysical artifacts from the data products. As part of the CV effort detailed surface topography was mapped by NASA's Airborne Topographic Mapper (ATM) scanning laser over sites in Greenland, western US and the Dry Valleys in Antarctica. Ice sheet surface elevations mapped by airborne laser altimetry surveys also serve as baselines for the ICESat mission. Here we present results from two different projects in the Antarctica. Detailed surface topography, derived from ATM data, is used to verify the ICESat products over the Dry Valleys. Surface elevations, mapped by the University of Texas airborne system (former Support Office of Airborne Geophysics), serves as baselines to map changes over the West Antarctic Ice Sheet ice streams. ATM surveys were conducted over the Dry Valleys in December 2001 in collaboration with NSF and USGS. In addition to survey candidate calibration/validation sites for the ICESat mission, the campaign was going to support NSF projects and to provide data to evaluate the potential of the use of laser altimetry in the Antarctica. The survey resulted blanket coverage over several sites. We have developed a procedure using robust estimation techniques to remove the outlier observations and to interpolate the data into regular grids (DEMs). The ICESat elevation and waveform products were verified by comparing them with the DEMs and with simulated waveforms. Surface reflectivity, necessary for the waveform simulation, was derived from satellite imagery. The stable terrain of the site makes it ideal for serving as benchmark surface throughout the ICESat mission. Precise repeat laser altimetry surveys were conducted with the SOAR system in 1997/98 and 1999/2000 over portions of the Whillans ice stream and ice streams C and E, West Antarctica. It is well known that these ice streams are undergoing substantial changes in length, width, thickness and speed at decadal and shorter changes. We determined elevation changes during the last 5 years by comparing elevations measured by ICESat over the 8-day repeat orbits with the results of the SOAR surveys. We plan to use the 91-day repeat ICESat data to investigate the details of the surface change pattern.
DE: 1640 Remote sensing
DE: 1655 Water cycles (1836)
DE: 1694 Instruments and techniques
DE: 1863 Snow and ice (1827)
DE: 3309 Climatology (1620)
SC: Cryosphere [C]
MN: 2003 Fall Meeting