HR: 10:50h
AN: G31C-03    [PDF]
TI: Contributions of surface fluid reservoirs of the late 90's anomaly of the Earth's oblateness
AU: * Ramillien, G
EM: Guillaume.Ramillien@cnes.fr
AF: LEGOS-GRGS/CNES, 18, Avenue Edouard Belin 31 055 Toulouse Cedex 01 FRANCE, Toulouse, 31400 France, Metropolitan
AU: Soudant, P
EM: soudant@notos.cst.cnes.fr
AF: LEGOS-GRGS/CNES, 18, Avenue Edouard Belin 31 055 Toulouse Cedex 01 FRANCE, Toulouse, 31400 France, Metropolitan
AU: Cazenave, A
EM: Anny.Cazenave@cnes.fr
AF: LEGOS-GRGS/CNES, 18, Avenue Edouard Belin 31 055 Toulouse Cedex 01 FRANCE, Toulouse, 31400 France, Metropolitan
AB: Recent satellite measurements have revealed a sudden change in the behaviour of the J2 (i.e. Earth's oblateness) time-series (Cox and Chao, 2002). Such an anomaly suggests an important redistribution of mass at the surface of the Earth from the high-latitude to the equatorial regions. In particular, air and water masse inside surface reservoirs (atmosphere, oceans, continental water storage -soil moisture, ground water, snow depth and ice reservoirs- (Cox and Chao, 2002, Dickey et al., 2002, Nerem et al., 2002, 2003, Chao et al., 2003)). In this study, we have reconsidered the long time-seriesof each fluid contribution using outputs of global atmosphere, ocean and hydrology models (ECMWF and NCEP for atmospheric surface pressure; POCM, OPA, MIT simulations and ECCO assimilation for ocean bottom pressure; LaD model for continental waters -soil moisture, groundwater,and snow cover- ). We have also considered the contribution of mountain glaciers melting using data from NSIDC. We show that the J2 anomaly bulge of 1998-2000 coincides with a significant increase of the degree-2 zonal harmonic of the oceans. Empirical Orthogonal Functions (EOF) analyses of the atmospheric, oceanic and hydrological fields allow us to better understand the importance of each contribution.
DE: 1200 GEODESY AND GRAVITY
DE: 1223 Ocean/Earth/atmosphere interactions (3339)
SC: Geodesy [G]
MN: 2003 Fall Meeting