A SENSITIVITY STUDY OF THE GENERAL-CIRCULATION OF THE WESTERN MEDITERRANEAN SEA .2. THE RESPONSE TO ATMOSPHERIC FORCING

This paper investigator the influence of sea surface thermohaline flux es and wind stress on the circulation of the Western Mediterranean Sea using a high-resolution 3D primitive equation model. An 18-year exper iment was forced with the daily output of a fine grid mesh numerical w eather prediction model. The major characteristics of the circulation are well reproduced. The basin surface circulation is cyclonic over al l of the basin. The two anticyclonic Alboran gyres are present. The in stabilities of the Algerian Current generate large anticyclonic eddies that invade the whole Algerian Basin, The Liguro-Provencal-Catalan Cu rrent is well marked. Deep water convection down to the bottom only oc curs during the-first 3 years, then winter intermediate water is produ ced. The north-south gradient of the atmospheric thermohaline fluxes i nduces a northward surface transport of water from the Algerian Basin into the Liguro-Provencal Basin. This pattern can be associated with t he Balearic front. Sensitivity experiments show that the wind stress c url reinforces the cyclonic circulation of the Liguro-Provencal Basin through a Sverdrup balance mechanism and contributes to deep-water for mation. It is also suggested that the variations of the transport in t he Corsican Channel are linked to the wind stress action rather than t he heat flux gradient between the Tyrrhenian and Ligurian Seas.