Satellite observation of sharp frontal shear instabilities and surface jets in the Mediterranean Sea

In this study we analyse thermal satellite images relative to years 1997-2000, to infer cold filaments and surface jets dynamics in the Mediterranean Sea. The main zones in which these phenomena are seen to occur are characterised by upwelling and/or the funnelling of strong cold winds by somewhat irregular coastal topography. Indeed, intense air-sea interaction in the coastal zone are known to generate a particularly strong input of potential vorticity into marine water, and this in turn gives origin to upwellings, cold filaments and jets. In the Mediterranean Sea, the geographical zones more "rich" in these jets are the two lobes of the southern Sicilian coast, the sea off Olbia in Sardinia, that South of the island of Crete, where a particularly intense large scale turbulence field is evident, and the Balkanic coast of the Adriatic sea. In addition, the theoretical analysis of these jets' evolution using a modern version of the potential vorticity conservation, valid even if friction and entrainment are to be considered , gives some insight into these systems' dynamics.