An accurate knowledge of ocean tides contribution is required for altimetry so as to eliminate tide contribution and access to oceanic signal associated with global oceanic circulation. Tide gauge data of WOCE Sea Level component allow to validate numerous tide models. Then FES94 hydrodynamic model developed in Grenoble (France) by the Christian Le Provost team was more accurate than earlier hydrodynamic models. To improve this model, a tide gauge assimilation method for hydrodynamic tide model was developped in Toulouse (LEGOS). This new tide model was choosen to correct Topex/Poseidon and Jason1 satellite altimetric measures. Sea level data are sparse in the South Indian Ocean. ROSAME tide gauge data bring accurate informations which are used in new hydrodynamic model assimilation : computed ocean tides are mainly improved in these subantarctic areas.
