  We use Lagrangian diagnostics (the leaking and the exchange methods) to
characterize surface transport out of and between selected regions in the
Western Mediterranean. Velocity fields are obtained from a numerical model.
Residence times of water of Atlantic origin in the Algerian basin, with a
strong seasonal dependence, are calculated. Exchange rates between these waters
and the ones occupying the northern basin are also evaluated. At surface,
northward transport is dominant, and involves filamental features and eddy
structures that can be identified with the Algerian eddies. The impact on these
results of the presence of small scale turbulent motions is evaluated by adding
Lagrangian diffusion.
