The Role of an Intense Front on the Connectivity of the Western Mediterranean Sea: The Cartagena-Tenes Front

A combined space and time domain Self-Organizing Maps analysis of Altimetry-derived finite-size Lyapunov exponents is used to extract characteristic spatial patterns of mesoscale features and to classify the western Mediterranean in regions of different variability of mixing activity. In particular, a recurrent and intense front is unveiled between Cartagena, Spain, and Tenes, Algeria, in the eastern boundary of the Alboran Sea, the here called Cartagena-Tenes front (CTF). The temporal evolution and the frequency of occurrence of the spatial patterns and the regional variability of the mixing structures together with additional complementary Lagrangian diagnosis have been used to investigate the effect of the CFT on the regional flow connectivity. The seasonal behavior in the flux of particles through the domain associated with the degree of activation of the CTF shows that surface connectivity between the Alboran Sea and the western Mediterranean is stronger during winter and spring when the CTF is not active. Furthermore, the analysis shows that CTF becomes stronger than the Almeria-Oran front over particular time periods, controlling the transport processes in this area. The impact of these fronts on transported substances has been analyzed based on Chlorophyll-a satellite distribution, showing how the Lagrangian Coherent Structures, separate regions of different connectivity properties, affecting on the dynamical and biological behavior.