HR: 1330h
AN: C32A-0441    [PDF]
TI: Validation of satellite altimeter range measurements over salar de Uyuni, Bolivia
AU: * Fricker, H A
EM: hafricker@ucsd.edu
AF: Scripps Institution of Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography U.C. San Diego, La Jolla, CA 92093 United States
AU: Roca, M
EM: monica.roca@pildo.com
AF: Delft Institute for Earth-Oriented Space Research (DEOS), Faculty of Aerospace Engineering Delft University of Technology, Delft, NL-2600 GA Netherlands
AU: Laxon, S W
EM: enquiries@cpom.ucl.ac.uk
AF: Department of Space and Climate Physics, University College London Gower Street, London, WC1E6BT United Kingdom
AU: Carabajal, C C
EM: claudia@stokes.gsfc.nasa.gov
AF: NVI, Inc. at Goddard Space Flight Center, Space Geodesy Branch Mailcode 926, Greenbelt, MD 20771 United States
AU: Quinn, K
EM: katyq@chandler.mit.edu
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Borsa, A A
EM: aborsa@ucsd.edu
AF: Scripps Institution of Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography U.C. San Diego, La Jolla, CA 92093 United States
AU: Minster, J B
EM: jbminster@ucsd.edu
AF: Scripps Institution of Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography U.C. San Diego, La Jolla, CA 92093 United States
AB: The salar de Uyuni in the Bolivian altiplano covers approximately 9600 km$^{2}$, and is the largest dry salt lake in the world. This vast, flat stable surface is ideal for estimation of the range bias on altimeter instruments such as GLAS on board ICESat (launched 12th January 2003), RA-2 on board ENVISAT (launched March 1st 2002) and the ERS-2 radar altimeter (RA, launched 1995), and to compare the measurements from these altimeters. Here we describe a kinematic GPS survey of the salar de Uyuni that was carried out in August/September 2002 and was designed to calibrate GLAS and RA-2. The eastern part of the salar was surveyed with 8 grids 22.5 km x 13.5 km at 2.25 km spacing, and with 2 grids which straddled one ascending and one descending ERS-2/ENVISAT orbit across this part of the salar, one 44.5 x 9 km, the other 18 x 13.5 km. Comparison of GPS heights from one GPS grid to the next and crossover analysis at intersections suggests that RMS accuracy of the GPS measurement is around 2 cm. We retracked the altimeter waveforms by fitting the system point target response to retrieve the altimeter surface elevation. We fitted a gaussian-smoothed surface to the GPS heights collected around the ERS-2/ENVISAT grids and interpolated these surfaces to the locations of altimeter footprints to obtain an estimate of the range bias for each instruments (GLAS, RA-2 and the ERS-2 RA). We also compare our results with data from one cycle of TOPEX data, which was collected during an orbit manoeuvre phase in September 2002. Ground tracks from this cycle serendipitously crossed our survey area at the same time we were on the ground.
DE: 1640 Remote sensing
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2003 Fall Meeting