The Climatological Seasonal Circulation of the Mediterranean Sea

Abstract

The horizontal circulation of the upper 800 m of the Mediterranean Sea is calculated from a seasonal climatological hydrographic data set using a simple inverse model. The results show a fairly steady surface circulation in the western Mediterranean and a somewhat stronger seasonal signal in the surface circulation of the eastern Mediterranean. The deep flow field can be calculated for most of the Mediterranean, except for the Levantine basin east of Crete, where the high noise level in the data masks the deep circulation. The calculated deep velocity field (below 500 m) shows some interesting features, including several steady cyclonic gyres in the West Mediterranean and in the Ionian basin of the East Mediterranean. In particular, the path of Levantine Intermediate water from the straits of Sicily toward the straits of Gibraltar is found to be along the Sardinian, French and then Spanish and Majorca coasts, and not directly along the African coast. The robustness of the inverse model results for the deep velocity field is demonstrated by examining several variations of the model (with and without mixing, different initial reference levels, etc). The model also calculates long- and cross-isopycnal mixing coefficients for the temperature and salinity but the error bars calculated for these parameters are large, and they are found not to be significantly different from zero.