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Satellite altimetry and marine gravity data: toward a consistent knowledge of the gravity field.

Marie-Françoise Lequentrec-Lalancette(1) and Didier Rouxel(1)

(1) SHOM, 13 rue du Chatellier - BP30316, 29603 BREST Cedex, France

Abstract

Since the sixties, marine gravity measurements are done in the oceans and the oceanic area was gradually covered by the gravity marine surveys. The launching of the first altimetric satellites in the eighties had a great impact on the global marine gravity knowledge. The global models of mean sea surfaces or of the free air anomalies were universally used and lead to a lot of results in oceanography or earth geophysics in the oceans. Nevertheless, these models don’t answer all questions especially in the study of the short wavelengths of the free air anomaly or bathymetry. From few examples the case of mixing derived altimetric free air anomaly grid with marine measurements will be studied. We will show in this paper the own contribution of satellite altimetry and marine gravity in the knowledge of marine gravity disturbances. The use of satellite altimetric data to homogenize the gravity measurements will be described. To recover the high frequencies of the gravity, a new method of enrichment of global gravity model by bathymetric information will be presented. The results show that the merging of these data conducts to precise gravity modelling at high spatial resolution. In the future, the GOCE data allow to obtain better referenced altimetric data due to the very precise geoid and to improve our model.

 

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                 Last modified: 07.10.03