Alborán sea shelf hydrodynamic processes

Abstract

The Alborán Sea is a back-arc region located in the western Mediterranean Sea. This region is connected to the Atlantic Ocean through the Gibraltar Strait and opens to the east into the Balearic Basin through the Alborán Trough. In the Alborán Sea, oceanic motions involve a great variety of both spatial and temporal scales. The influence of tides, subinertial flow induced by atmospheric pressure gradients and wind stress, and the wind waves near the coast has been intensively studied. However, a detailed study of long-period waves, as Continental Shelf Waves (CSWs), propagating along the continental shelves of the Alborán Sea is still lacking. This type of waves propagates in one direction with the coast on the right (Northern Hemisphere). The presence of two narrow, opposite, and approximately parallel continental shelves provides an additional interest to the study site, because of the possible interaction of these kind of waves travelling in opposite directions. Then, this Thesis studies the existence of these waves in the continental shelves of the Alborán Sea. Another special feature of the Alborán Sea is that it is indented by transverse incisions. Some of these incisions are large enough to be considered submarine canyons. Several studies suggest that wind modifies the circulation in submarine canyons and drives cross-shore transports and vertical motions. However, little is known on the role of local atmospheric pressure gradients on the circulation of a submarine canyon. This Thesis also explores the role of this forcing in the circulation of a submarine canyon of the Alborán Sea, the Jolúcar canyon. Thus, the general aim of this Thesis is to study hydrodynamic processes over the continental shelves (northern and southern) of Alborán Sea (regional scale) and the local circulation in a submarine canyon indenting in the northern shelf. The objective is addressed using data analysis of field observations, and semi-analytical models.