Water masses and circulation between the eastern Algerian Basin and the Strait of Sicily in October 1996

Abstract

The investigation is based on data collected between the eastern Algerian Basin and the Strait of Sicily and in the southern Tyrrhenian Sea. The major pathways of water masses are identified by the core method and geostrophic currents are derived from the objectively analysed density field. Between the Sardinia Channel and the Strait of Sicily, the large-scale circulation of Modified Atlantic Water and Winter Intermediate Water is found to be cyclonic. Inflow into the gyre occurs via the Sardinia Channel by means of a boundary current attached to the Algerian coast, and from the northern Tyrrhenian. The outflow is accomplished via the Strait of Sicily and to the Tyrrhenian. The Levantine intermediate water flow resembles that of Modified Atlantic Water/Winter Intermediate Water in the southern Tyrrhenian, but it is opposed in the Strait of Sicily and off Tunisia. Outflow to the Algerian Basin occurs south of Sardinia. In the eastern Algerian Basin the flow direction of all water masses is eastward close to the Algerian shelf. Farther offshore, Modified Atlantic Water flows mainly southwest whereas the Levantine Intermediate Water is opposed to that supporting northward transport along the Sardinian shelf. The large-scale flow of all water masses is perturbed by mesoscale eddies. The impact of topographic obstacles is investigated.