Reconstruction of the Mediterranean northern current variability and associated cross-shelf transport in the Gulf of Lions from satellite-tracked drifters and model outputs

The reconstruction of currents at 50 m depth was performed in the Gulf of Lions, merging Lagrangian data with outputs from a numerical ocean model. The Lagrangian data set consists of trajectories obtained from 12 satellite-tracked drifters released in the Northern Current in June 2005. The low-pass filtered trajectories revealed the well-known mean patterns of along-slope circulation and sampled its mesoscale activity, showing meandering pathways over the slope and closed pathways trapped over the shelf. They were used to reorganise the model eddy activity by refining the location and shape of meanders and eddies. The impacts of the reconstruction procedure were assessed by comparing the simulated and reconstructed fields with simultaneous SST images. Finally, the reconstructed fields were used to study some of the observed mesoscale structures. They provide a realistic scenario for diagnostics of the shelf-slope transports in the Gulf of Lions.