HR: 15:55h
AN: G23A-09    [Abstracts]
TI: Verification of basin-scale ocean mass variations from GRACE using altimetry and heat storage
AU: * Leuliette, E W
EM: Eric.Leuliette@colorado.edu
AF: University of Colorado at Boulder, 431 UCB/CCAR, Boulder, CO 80309-0431
AU: Nerem, R S
EM: nerem@colorado.edu
AF: University of Colorado at Boulder, 431 UCB/CCAR, Boulder, CO 80309-0431
AB: Empirical orthogonal analysis of the initially released GRACE gravity fields reveals that roughly half of the variance can be attributed to a single spatial mode with a seasonal signal. Tapley et al. [2004] and Wahr et al. [2004] demonstrated that the seasonal signal in the GRACE fields is consistent with the gravity signal expected from ocean and hydrological models. Recently, the preliminary GRACE observations have been used to derive an estimate of global ocean mass variations. Chambers, Wahr, and Nerem [2004] compared this time-series to a mean climatology determined from satellite altimeter measurements of global mean sea level corrected for the steric variation. The GRACE observations show a seasonal exchange of water mass with the continents of the same magnitude and phase as the steric-corrected altimetry. We present estimates of ocean mass variations using the latest GRACE fields for each ocean basin. In addition to using a mean climatology to steric-correct TOPEX/POSEIDON and Jason altimetry data, we also derive a thermal steric height variation from monthly upper ocean heat storage estimates from the Joint Environmental Data Analysis Center (JEDAC). The JEDAC heat storage fields have been generated from observed temperature profiles (e.g. expendable bathythermograph data). We also present basin-scale comparisons using ECCO model output to steric-correct altimetry data. Finally, preliminary results of secular variations of ocean mass will be discussed.
DE: 4556 Sea level variations
DE: 1655 Water cycles (1836)
DE: 1836 Hydrologic budget (1655)
DE: 1200 GEODESY AND GRAVITY
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting