Mardi 28 juin - New insights on upper layer circulation in the Gulf of Guinea
de 13:30 à 14:30
|Où ?||Salle Lyot|
Gaelle Herbert, Post-doctorante, IRD-Ifremer Brest
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IRD - IFREMER Brest
Titre : New insights on upper layer circulation in the Gulf of Guinea
The oceanic circulation in the upper layers of the north of the Gulf of Guinea is analyzed, as inferred from in situ observations and numerical simulations. This particular region, in spite of the presence of a coastal upwelling and its impact on resources and regional climate, is still poorly documented. Cruises carried out in the framework of different international programs (e.g. EGEE/AMMA, PIRATA) allowed to show in the north of the Gulf of Guinea the existence of an eastward flowing undercurrent, found under the Guinea Current, named the Guinea UnderCurrent (GUC). Numerical results from high resolution simulation allowed the description of the seasonal variability of this current. We also depict the fate and the sources of the GUC based on selected trajectories from numerical particle tracking. The results reveal several new insights which help us to clarify still open questions on the regional circulation dynamics in the Gulf of Guinea. In particular, lagrangian experiments show that the GUC is not an extension of the North Equatorial UnderCurrent and confirm that this current does not penetrate into the Gulf of Guinea. On the other hand, ongoing studies in the southeast of the Gulf of Guinea as inferred from an interannual high resolution model and in-situ and satellite data will also be presented.