The hydrodynamics of the Western Mediterranean Sea

Euromodel is devoted to process studies in relation to the description, understanding and simulation of the seasonal and mesoscale variability of the general circulation of the Western Mediterranean. Deep water formation drives the large cyclonic gyre observed in the northern basin. Some seasonal and mesoscale characteristics of the Northern, Tyrrhenian and Western Corsican Currents are specifies. The flow throuch the strait of Gibraltar is not hydraulically controlled. Potential vorticity conservation and changes in the meridional pressure gradients explain the formation of the western Alboran Sea gyre. Cyclonic eddies at its periphery are observed and modelled. The Almeria-Oran jet-front system is described in terms of geostrophic adjustment of Modified Atlantic Water and Mediterranean Water. Algerian eddies are linked to baroclinic instability of the current. A cyclonic circulation around the continental slope in the whole western basin is observed at depth. Upper ocean mesoscale variability is related to downward penetration of near-inertial motions as observed near the Catalan front. In the Balearic Sea, spatial and temporal variability of two shelf / slope fronts influences the large scale dynamics. The MAST 1 phase of Euromodel, initiales a numerical simulation of the Western Mediterranean : the sole forcing by the density gradients throuh the straites of Gibraltar and Sicily quaalitatively reproduces the basin scale cycloni surface and intermediate flows and the coastal currents.