Deep-sea circulation in the Alboran sea

Abstract

Alboran Sea circulation between 220 and 1100 m depth is studied. Interaction between three types of water masses in this area causes a complicated flow pattern. Atlantic water flowing as a jet through the Strait of Gibraltar into the Mediterranean often forms an anticyclonic gyre to the depth of 200 m, and its features are now well documented. A few works based on geostrophic calculations and Bernoulli's equation treat the deep flow. Nine free floats were released at different depths and locations from January to May 1982 and acoustically tracked every 2 hours for 40 to 90 days. Acoustical tracking was done from three listening stations moored in the area. The tracks of the floats at all depths from 220 to 1100 m revealed broad and slow (approximately 2.5 cm/s) cyclonic circulation located under the surface anticyclonic gyre. Part of the flow, following the bottom topography, turned near the Moroccan Continental slope as a jet (approximately 5 cm/s) to Gibraltar and part turned to the east following the southern boundary of the deep channel to the Isle of Alboran.