Articles | Volume 13, issue 2
Research article
24 Mar 2017
Research article |  | 24 Mar 2017

The Mediterranean outflow in the Strait of Gibraltar and its connection with upstream conditions in the Alborán Sea

Jesús García-Lafuente, Cristina Naranjo, Simone Sammartino, José C. Sánchez-Garrido, and Javier Delgado

Abstract. The present study addresses the hypothesis that the Western Alborán Gyre in the Alborán Sea (the westernmost Mediterranean basin adjacent to the Strait of Gibraltar) influences the composition of the outflow through the Strait of Gibraltar. The process invoked is that strong and well-developed gyres help to evacuate the Western Mediterranean Deep Water from the Alborán basin, thus increasing its presence in the outflow, whereas weak gyres facilitate the outflow of Levantine and other intermediate waters. To this aim, in situ observations collected at the Camarinal (the main) and Espartel (the westernmost) sills of the strait have been analysed along with altimetry data, which were employed to obtain a proxy of the strength of the gyre. An encouraging correlation of the expected sign was observed between the time series of potential temperature at the Espartel Sill, which is shown to keep information on the outflow composition, and the proxy of the Western Alborán Gyre, suggesting the correctness of the hypothesis, although the weakness of the involved signals does not allow for drawing definitive conclusions.

Short summary
This study shows the influence of the Western Alboran circulation on the composition of the outflow through the Strait of Gibraltar, which is mainly composed by intermediate and Deep Mediterranean Water. While the effect of the gyre in the deep water proportion was already reported, the effect on the intermediate flow has not been addressed yet. The size of the gyre was compared with the characteristic of the outflow in the strait. Results show the intermediate flow benefits from a weak gyre.