HR: 0800h
AN: G31C-0814    [Abstracts]
TI: Assessment of GRACE Time-Variable Gravity Observables: A New Filtering Technique to Enhance Signal Spatial Resolutions
AU: Shum, C
EM: ckshum@osu.edu
AF: Laboratory for Space Geodesy and Remote Sensing, Geodetic Science, Ohio State University, 2070 Neil Avenue, Columbus, OH 43210-1275 United States
AU: * Han, S
EM: han.104@osu.edu
AF: Laboratory for Space Geodesy and Remote Sensing, Geodetic Science, Ohio State University, 2070 Neil Avenue, Columbus, OH 43210-1275 United States
AU: Kuo, C
EM: kuo.70@osu.edu
AF: Laboratory for Space Geodesy and Remote Sensing, Geodetic Science, Ohio State University, 2070 Neil Avenue, Columbus, OH 43210-1275 United States
AU: Seo, K
EM: kiweon@geo.utexas.edu
AF: Department of Geological Sciences, Jackson School of Geosciences, University of Texas, 1 University Station C1100, Austin, TX 78712-0254 United States
AU: Wilson, C
EM: clarkw@maestro.geo.utexas.edu
AF: Department of Geological Sciences, Jackson School of Geosciences, University of Texas, 1 University Station C1100, Austin, TX 78712-0254 United States
AU: Wilson, C
EM: clarkw@maestro.geo.utexas.edu
AF: Center for Space Research, University of Texas, 3925 West Braker Lane, Suite 200, Austin, TX 78759-5321 United States
AB: A contemporary filter based on the Gaussian smoother assumes a degree dependent error in the satellite geopotential coefficient estimates (Wahr et al., 1998). It effectively damps the power of ill-determined higher spatial frequency estimates. Wahr et al. (2004) shows that the current release of GRACE L2 monthly geopotential data product has the sensitivity up to degree and order 15 in spherical harmonics, and that GRACE error dominates beyond degree 15. Here, we study the correlations between the GRACE estimates and combination of hydrology and ocean models, with an objective to investigate the possibility of preserving higher frequency GRACE signals from the L2 data product. In particular, we have developed a filter to optimize the degree and order dependence of the GRACE geopotential error. The filter is dependent on the correlation between the GRACE L2 and predictions based on geophysical models (i.e., hydrological and ocean models). In order to retain the GRACE coefficients showing reasonable correlation with the models, we applied Gaussian smoothers with different averaging radii to the different orders. It provides higher resolution in latitude and the same resolution in longitude as the standard Gaussian smoother. We present the results based on both filters and discuss the advantage of the new filter by processing two years of GRACE L2 geopotential coefficients.
DE: 1800 HYDROLOGY
DE: 1200 GEODESY AND GRAVITY
DE: 1214 Geopotential theory and determination
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
DE: 1241 Satellite orbits
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting