HR: 1340h
AN: G33B-0035    [Abstracts]
TI: Low Degree Spherical Harmonic Influences on Basin-Scale Water Storage Change from GRACE
AU: * Chen, J
EM: chen@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Lane, Suite 200, Austin, TX 78759
AU: Wilson, C
EM: crwilson@mail.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker Lane, Suite 200, Austin, TX 78759
AU: Wilson, C
EM: crwilson@mail.utexas.edu
AF: Department of Geological Sciences, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712
AU: Rodell, M
EM: Matthew.Rodell@nasa.gov
AF: GSFC Hydrological Sciences Branch, Code 614.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771
AU: Famiglietti, J
EM: jfamigli@uci.edu
AF: Department of Earth System Science, University of California, Irvine, CA 92697
AB: We estimate terrestrial water storage variations using time variable gravity changes observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during the first 2 years of the mission. We examine how treatment of low-degree gravitational changes and geocenter variations affect GRACE based estimates of basin-scale water storage changes, using independently derived low-degree harmonics from Earth rotation (EOP) and satellite laser ranging (SLR) observations. GRACE based water storage changes are compared with estimates from NASA's Global Land Data Assimilation System (GLDAS). Results from the 22 GRACE monthly gravity solutions, covering the period April 2002 to July 2004, show remarkably good agreement with GLDAS in the Mississippi, Amazon, Ganges, Ob, Zambezi, and Victoria basins. Combining GRACE observations with EOP and SLR degree-2 spherical harmonic coefficient changes and SLR observed geocenter variations significantly affects and apparently improves the estimates, especially in the Mississippi, Ob, and Victoria basins. Water storage estimates in polar regions, e.g., Antarctic and Greenland are particularly sensitive to the low degree harmonic changes.
UR: http://www.agu.org/pubs/crossref/2005/2005GL022964.shtml
DE: 1200 GEODESY AND GRAVITY
DE: 1217 Time variable gravity (7223, 7230)
DE: 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
SC: Geodesy [G]
MN: Fall Meeting 2005