HR: 14:55h
AN: G23A-06    [Abstracts]
TI: Independent Determinations of Low Degree Gravitational Change
AU: * Chen, J
EM: chen@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. braker Lane, # 200, Austin, TX 78759
AU: Wilson, C
EM: clarkw@maestro.geo.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. braker Lane, # 200, Austin, TX 78759
AU: Wilson, C
EM: clarkw@maestro.geo.utexas.edu
AF: Department of Geological Sciences, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712
AU: Tapley, B
EM: tapley@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. braker Lane, # 200, Austin, TX 78759
AB: We examine low degree gravitational variations of C21, S21, and C20 observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during the first 2 years of this gravity mission. The GRACE observations are compared with independent estimates from accurately measured Earth rotational changes and predictions from atmospheric, oceanic, and hydrological models. The 18 GRACE monthly gravity solutions, covering the period April 2002 to March 2004, show strong seasonal variability in the C21, D21, and C20 time series, and generally agree with Earth rotation-derived changes and geophysical model estimates, in particular in S21 and C20. Earth rotation-derived results agree very well with geophysical model predictions from advance atmospheric, oceanic, and hydrological models, in particular in the two non-zonal terms (i.e., C21 and S21). The differences between GRACE results and Earth rotation-derived estimates, especially in C21 are likely caused by the errors in the background models used in GRACE data processing.
DE: 1200 GEODESY AND GRAVITY
DE: 1214 Geopotential theory and determination
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 1239 Rotational variations
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting