Combination of NOAA/AVHRR Images and Topex/Poseidon Data to Analyse the Mesoscale Phenomena in the Algerian Basin (in the Western Mediterranean Sea)
Mega Nabil(1) and Lansari Abdeldjelil(1)
National Centre for Space Techniques,
1, Avenue of Palestine, Arzew,
Even though the circulation of the various water masses in the Western Mediterranean Sea can now be considered as roughly described, several features are not reproduced by the numerical models. Therefore, the functioning of the whole sea is certainly not well understood yet. The major questions concerning the Gulf of Lions and the Algerian Basin are as follow.
In this project, we are interested to study the physical structure of mesoscale phenomena resulting from the instability of coastal current has still to be specified, significant results have been obtained about the Algerian Current system. Obviously, the interaction of an event with the topography at the channel of Sardinia entrance, and its transformation into an open-sea eddy isolated from its parent current, are complex problems that cannot be solved with the available date sets (NOAA/AVHRR images). The dynamic topography of the sea surface is directly related to the oceanic currents. In order to obtain details of circulation, it is interesting to use the altimetric data of the satellites altimeters, such as for example TOPEX/POSEIDON, to obtain a denser space-time sampling. The combination of two types of satellite data made it possible to observe, for the first time by altimetry, the principal characteristics of circulation in the western Mediterranean sea and in particular the seasonal variations. The cartography of the Sea Surface Height (SSH) highlights the intensification of oceanic circulation. Nevertheless, the anticlockwise circuit of the Algerian eddies in the eastern Algerian Basin is definitively demonstrated. The essential goal of this study is to establish a cartography of a high degree of accuracy of the average surface of the Algerian basin in the Western Mediterranean sea, and also to observe the space and temporal variability surface marine, precisely, the anticyclonic eddies through short and long-term.