HR: 09:45h
AN: H21C-08    [PDF]
TI: Measuring Large-Scale Changes in Water Storage from Space: First Results from GRACE
AU: * Swenson, S C
EM: swensosc@colorado.edu
AF: University of Colorado, Dept. of Physics and CIRES, Campus Box 390, Boulder, CO 80309
AU: Wahr, J
EM: wahr@lemond.colorado.edu
AF: University of Colorado, Dept. of Physics and CIRES, Campus Box 390, Boulder, CO 80309
AB: The satellite Gravity Recovery and Climate Experiment (GRACE) provides data estimating monthly changes in the Earth's gravity field, which are in part due to changes in vertically integrated terrestrial water storage. Unlike conventional point or gridded hydrologic measurements, such as those from rain gauges, stream gauges, rain radars, and radiometric satellite images, GRACE data are comprised of the spectral coefficients describing the Earth's gravity field. These coefficients can be inverted to solve for spatially averaged changes in continental water storage. Because the data are more accurate at longer length scales, spatial averages become more accurate as the area of the region increases. Therefore, GRACE provides direct measurements which can be used to close the water budget at regional to global length scales. GRACE data can thus be used to assess modelled large-scale water-balance predictions. In addition, GRACE data combined with river gauge data can provide estimates of precipitation minus evapotranspiration spatially averaged over large river basins. We will present the first comparisons of GRACE water storage estimates with hydrologic models and gauge data.
DE: 1640 Remote sensing
DE: 1829 Groundwater hydrology
DE: 1836 Hydrologic budget (1655)
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting