About the seasonal variability of the Alboran Sea circulation

• Published in: Journal of marine systems Vol. 35; no. 3; pp. 229 - 248
• Main Authors: Vargas-Yáñez, M, Plaza, F, Garcı́a-Lafuente, J, Sarhan, T, Vargas, J.M, Vélez-Belchi, P
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 01.07.2002; Elsevier
• Subjects: Alboran Sea; Earth, ocean, space; Exact sciences and technology; External geophysics; Gibraltar Strait; Marine; Physics of the oceans; Seasonal variability; Thermohaline structure and circulation. Turbulence and diffusion; Gibraltar Strait; Mediterranean Sea; Alboran Sea; MED, Alboran Sea; MED, Alboran Sea, Western Alboran Gyre; MED, Spain, Andalucia, Almeria, Alboran I; MED, Gibraltar Strait; Seasonal variability; Gibraltar Strait; Alboran Sea; Annual variation; Seasonal variation; Mooring; Time series; Sea circulation; Sea level; Semiannual variation; Time variation; Salinity
• ISSN: 0924-7963; 1879-1573
• DOI: 10.1016/S0924-7963(02)00128-8

Data from a mooring line deployed midway between the Alboran Island and Cape Tres Forcas are used to study the time variability of the Alboran Sea from May 1997 to May 1998. The upper layer salinity and zonal velocity present annual and semiannual cycles characterised by a minimum in spring and autumn and a maximum in summer and winter. Temperature has the opposite behaviour to that of salinity indicating changes in the presence of the Atlantic water within the Alboran Passage. A large set of SST images is used to study these cycles. The decrease of salinity and velocity in our mooring location in spring and autumn seems to be related to the eastward drifting of the Western Alboran Gyre (WAG). The increase of salinity and velocity is caused by the Atlantic current flowing south of the Alboran Island and its associated thermohaline front. Conductivity–temperature–depth (CTD) data from two cruises along the 3°W are coherent with current meters and SST interpretations. During the period analysed, summer months are characterised by the stability of the two-gyre system, while in winter, the circulation is characterised by a coastal jet flowing close to the African shore. We use sea level differences across the Strait of Gibraltar for studying the variability of the Atlantic inflow. We discuss the changes in the Alboran Sea circulation and its relation with the variability of the inertial radius of the Atlantic inflow. Though our results are speculative, we find a possible relation between the disappearance of the two-gyre system and a reversal of the circulation in Gibraltar. Longer time series are needed to conclude, but comparison with previous works makes us think that the seasonal cycle described from May 1997 to May 1998 could be the most likely one for the Alboran Sea upper layer.