Proceedings of the space and sea colloquium

The joint NASA/CNES Topex/Poseidon mission will be mainly dedicated to the large scale oceanic circulation observation. The satellite pay load will include two altimeters, one radiometer and two precise orbit determination systems, Doris and GPS. Such system will provide sea level measurements with an absolute decimetric accuracy. The satellite will be launched in June 92 for a 3 to 5 years long mission. Previous studies, based on Geosat data, have shown that a large scale signal as the seasonal signal of the Tropical Atlantic can be well recovered by altimetry. Comparisons with models and in-situ data emphasize the consistency of the altimetric results. However, local differences are observed which can be due to real oceanographic effects or to imperfections in the altimetric data. In order to discern and to characterize the various error sources, a careful validation of altimetric data is required. (D'après résumé d'auteur