Surface circulation in the central Mediterranean Sea as deduced from Lagrangian drifters in the 1990s

The surface circulation in the central Mediterranean, including the Sicily Channel, the southern Tyrrhenian and western Ionian seas, is studied using the data of more than 150 satellite-tracked drifters for the period spanning 1990-99. Pseudo-Eulerian maps of mean flow, eddy variability and energy levels are produced using all the data, the data sorted by seasons and the data divided in major wind categories, to study the circulation variability at meso to seasonal scales, and in terms of the local wind forcing. In general, the new results revealed by the drifter data confirm the general characteristics of the surface circulation as detected in previous Eulerian investigations. However, they provide a new broad quantitative description of the central Mediterranean surface circulation and they shed light on the dynamics of the Channel at large, including the Tunisian shelf and the area south of Malta, which shows unexpected characteristics of the surface velocity field, sometimes stagna...