Merging Multisatellite Altimeter Missions to Monitor the Mediterranean Sea

Satellite altimetry is considered as one of the most important input datasets for operational oceanography, as it provides surface dynamic topography measurements, which constitute a strong constraint to estimate and forecast the three-dimensional ocean state through data assimilation. In this work, we carry out a first study of merging the data of four altimeter missions [Jason-1, ERS-2, Topex/Poseidon and Geosat Follow-On] with the aim of obtaining high resolution maps capable to monitor the mesoscale variability in the Mediterranean Sea. The results show that the combination of Jason-1 + ERS-2 fails to reproduce some intense signals that are well recovered when the other satellites are added. The consistency between altimetry and other kind of data (e.g. Sea Surface Temperature, drifting buoys and coastal tide gauges) is significantly improved when four satellites are merged compared to the results derived from the two satellite configuration.