REMOLINOS DE MESOESCALA EN EL MEDITERRANEO

MESOSCALE EDDIES IN THE MEDITERRANEAN:
Coherent eddies observed in two dimensional turbulent flows have a structure with an
inner part called the core and an outer part called the circulation cell. The core
is characterized by a dominance of vorticity while the circulation cell is dominated
by deformation. The relative dominance is usually measured in terms of the
Okubo-Weiss parameter (W) which is negative in the core and positive in the
circulation cell. Thus the sign of W is, under
some limitations, a way to determine connected regions of concentrated vorticity
in the field. Due to the quasi-bidimensional nature
of ocean flows on isopycnal
surfaces, a criterion in terms of the Okubo-Weiss parameter
is applied as a way to identify the core for eddies in the ocean. This method allows to detect
the eddies in the Mediterranean sea from altimetric maps and the
analysis of their sizes suggests that a definition
of --intense-- eddies in terms of W can be roughly identified with mesoscale
eddies. In addition, eddies can be tracked through consecutive maps to systematically obtain their trajectories. The results show that Mediterranean
eddies are mainly located in specific areas of the Algerian Basin and the Levantine Basin.
The paths and circuits thus obtained are validated with the trajectories
of some eddies infered from AVHRR images.