Connectivity Analysis Applied to Mesoscale Eddies in the Western Mediterranean Basin

The Western Mediterranean basin (WMED) is characterized by the presence of energeticand dynamic mesoscale cyclonic and anticyclonic eddies. They mainly originate along the Algerianand the Northern currents and have a large influence on the basin circulation. Eddies can lastfor months, with longer lifetimes associated with the anticyclones, which can move far from theirareas of origin. As they partially isolate and transfer water masses, they also have an impact onwater properties (physical, chemical and biological), pollutant's dispersion and transport of eggs,larvae and planktonic organisms. In this study, a connectivity analysis method is applied to theanticyclonic eddies (AEs) identified by an automated hybrid detection and tracking algorithm southof 42oN in the WMED. The same methodology is also applied to the trajectories of Lagrangian surfacedrifters available in the study area. The purpose is to highlight the connections between differentareas of the basin linked to eddy activities in addition to the connectivity due to the mean surfacecirculation. Drifter data analysis showed that all the WMED sub-basins are strongly interconnected,with the mean surface circulation allowing a shortcut connection among many areas of the basin.The connectivity analysis of the AEs tracks shows that although AEs are ubiquitous in the WMED,their connectivity is limited to well-defined regions, depending on their origin location. Three mainregions: the south-western, the south-eastern and the northern parts of the basin are characterized byAEs recirculation, with sporadic export of eddies to the other WMED zones