Recent observations of the Alboran Sea frontal system

Abstract

Past studies in the Alboran Sea have shown the existence of a strong oceanic front during summer, yet few observations have been made in other seasons. This note presents two sets of XBT data obtained in the Alboran Sea in fall and winter, 1976–1977. These data indicate that the Alboran Sea Front persists throughout the year. It meanders from Gibraltar eastward through the basin, sometimes establishing a series of alternating anticyclonic and cyclonic gyres. The front is confined to the upper 200 m and has a typical width of 35 km. A horizontal temperature difference of 2–4°C is maintained across the front at a depth of 100 m. The Alboran Sea Front forms the northern half of an anticyclonic gyre in the western basin. This gyre has a diameter of 75–100 km and appears to be a normal feature of the circulation pattern. When cold surface water along the southern coast of Spain is entrained into the gyre, the main features of the Alboran Sea circulation are enhanced and can be seen clearly on satellite infrared imagery.