HR: 10:20h
AN: H22C-01    [Abstracts]
TI: High-resolution regional recovery and validation of GRACE hydrological signals
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: 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: Alsdorf, D
EM: alsdorf@geology.ohio-state.edu
AF: Mendenhall Laboratory, Department of Geological Sciences, Ohio State University, 125 S. Oval Mall, Columbus, OH 43210-1308 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: We investigate a new method and its results to estimate the GRACE time-variable gravity field with enhanced temporal and spatial resolutions. The method is based on a regional inversion of in situ (on-orbit) gravitational potential difference estimated through the conservation of energy principle [Jekeli, 1999; Han, 2004]. Unlike the contemporary method to extract the time-variable gravity signal from the GRACE Level-2 (L2) data product in the form of monthly geopotentials, our method utilizes the GRACE Level-1B (L1B) data (KBR range-rate, precise orbit, accelerometry, and attitude data) and geophysical inversion. It provides the regional time-variable gravity signals with simultaneous adjustment of other parameters such as inter-satellite orbital position and velocity vectors. As a result, we improve both the spatial and temporal resolutions of the gravity estimates and thus reduce the temporal aliasing effect. We present the processing results as a demonstration based on four months of GRACE L1B data, and the analysis based on the recently available two years of data. Using the determined gravitational potential difference profiles, the water mass redistributions of two of the world's largest river basins, the Amazon and Mississippi, are studied. The terrestrial water mass variations are estimated every 2 degrees in latitude and longitude, and for every 15 days. Results are presented to assess the accuracy and resolutions of the regional variations with the L2 data products and hydrological models such as the NOAA CPC and other available in situ data and models. In particular, river gauges and other data will be used to validate the observed regional GRACE hydrological measurements.
DE: 1800 HYDROLOGY
DE: 1829 Groundwater hydrology
DE: 1200 GEODESY AND GRAVITY
DE: 1214 Geopotential theory and determination
DE: 1241 Satellite orbits
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting