Sensitivity of the sea circulation to the atmospheric forcing in the Sicily Channel

We investigate the sensitivity of the sea surface circulation in the Sicily Channel to surface winds, using a 15-year long (1994-2008) air-sea coupled numerical simulation. Analysis is based on the clustering of six main wind regimes over the Sicily Channel domain. The analysis of the corresponding sea current clusters shows that sea circulation in this area is sensitive to surface wind patterns. This wind modulates the strength of the two main branches of the sea circulation in the Sicily Channel (i.e. the Atlantic Tunisian Current and the Atlantic Ionian Stream). The modulation of these two currents depends on the wind regime, and displays a strong seasonal variability. It is also shown that the sea circulation in the Sicily Channel is strongly controlled by the thermohaline circulation and the bathymetry (geostrophic current). However, the contribution to the total current of its ageostrophic component forced by the surface winds is significant, with a correlation coefficient varying from 0.3 to 0.7.