Analysis of the Senegalo-Mauritanian upwelling by processing satellite remote sensing observations with topological maps.

The Senegalo-Mauritanian upwelling is a very productive upwelling occurring along the West coast of Africa. Its seasonal and inter-annual variability south of 20degN was analyzed by processing ocean color data and sea surface temperature provided by satellite sensors. We used a classification methodology consisting in a neural network topological map and a hierarchical ascendant classification. Four classes can explain most of the variability of the upwelling. Its extent is maximum in February-March, minimum in August September. The variability is linked to that of the wind. The classes can be considered as statistical indices allowing us to investigate the variability of the upwelling.