HR: 0800h
AN: U21C-0630    [Abstracts]
TI: Annual, Seasonal, and Secular Changes in Time-Variable Gravity from GRACE
AU: * Lemoine, F G
EM: Frank.G.Lemoine@nasa.gov
AF: NASA Goddard Space Flight Center, Planetary Geodynamics Branch, Code 698, Greenbelt, MD 20771, United States
AU: Luthcke, S B
EM: Scott.B.Luthcke@nasa.gov
AF: NASA Goddard Space Flight Center, Planetary Geodynamics Branch, Code 698, Greenbelt, MD 20771, United States
AU: Klosko, S M
EM: sklosko@sgt-inc.com
AF: SGT. Inc., 7701 Greenbelt Road, Greenbelt, MD 20770, United States
AU: Rowlands, D D
EM: David.D.Rowlands@nasa.gov
AF: SGT. Inc., 7701 Greenbelt Road, Greenbelt, MD 20770, United States
AU: Chinn, D S
EM: Douglas.S.Chinn@nasa.gov
AF: SGT. Inc., 7701 Greenbelt Road, Greenbelt, MD 20770, United States
AU: McCarthy, J J
EM: jmccarthy@sgt-inc.com
AF: SGT. Inc., 7701 Greenbelt Road, Greenbelt, MD 20770, United States
AU: Ray, R D
EM: Richard.Ray@nasa.gov
AF: SGT. Inc., 7701 Greenbelt Road, Greenbelt, MD 20770, United States
AU: Boy, J
EM: jpboy@eost.u-strasbg.fr
AF: EOST/IPG, 5, rue Rene Descartes, Strasbourg, 67084, France
AB: The NASA/DLR GRACE mission, launched in 2002, has now operated for more than five years, producing monthly and ten-day snapshots of the variations of the gravity field of the Earth. The available solutions, either from spherical harmonics or from mascons, allow us new insights into the variations of surface gravity on the Earth at annual, inter-annual, and secular time scales. Our baseline time series, based on GGM02C, NCEP Atmospheric Gravity with IB, and GOT00 tides now is extended to July 2007, spanning four+ years, and we analyze both mascon and spherical harmonic solutions from this time series with respect to global hydrology variations. Our 4degx4deg mascon solutions are extended to cover all continental regions of the globe. Comparisons with hydrology (land-surface) models can offer insights into how these models might be improved. We compare our baseline time series, with new time series that include an updated Goddard Ocean Tide (GOT) model, ECMWF- 3hr atmosphere de-aliasing data, and the MOG-2D ocean dealiasing product. Finally, we intercompare the spherical harmonic solutions at low degree from GRACE from the various product centers (e.g., GFZ, CSR, GRGS), and look for secular signals in both the GSFC mascon and spherical harmonic solutions, taking care to compare the results for secular gravity field change with independent solutions developed over 25 years of independent tracking to geodetic satellites by Satellite Laser Ranging (SLR) and DORIS.
DE: 1217 Time variable gravity (7223, 7230)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1800 HYDROLOGY
SC: Union [U]
MN: 2007 Fall Meeting