Respective roles of the Guinea current and local winds on the coastal upwelling in the northern Gulf of Guinea

Respective roles of the Guinea current and local winds on the coastal upwelling in the northern Gulf of Guinea Djakouré S. auteur aut IRD Penven Pierrick auteur aut IRD Bourlès Bernard auteur aut IRD Koné V. auteur aut IRD Veitch J. auteur aut IRD text journalArticle eng text/pdf born digital access The northern Gulf of Guinea is a part of the eastern tropical Atlantic where oceanic conditions due to the presence of coastal upwelling may influence the regional climate and fisheries. The dynamics of this coastal upwelling is still poorly understood. A sensitivity experiment based on the Regional Oceanic Modeling System (ROMS) is carried out to assess the role of the detachment of the Guinea Current as a potential mechanism for coastal upwelling. This idealized experiment is performed by canceling the inertia terms responsible for the advection of momentum in the equations and comparing with a realistic experiment. The results exhibit two major differences. First, the Guinea Current is found to be highly sensitive to inertia, as it is no longer detached from the coast in the idealized experiment. The Guinea Current adjusts on an inertial boundary layer, the inertial terms defining its lateral extension. Second, the upwelling east of Cape Palmas disappears in absence of the Guinea Current detachment. This is in contrast with the upwelling east of Cape Three Points, which is still present. The results suggest that two different generation processes of the coastal upwelling need to be considered: the upwelling east of Cape Palmas (which is due to inertia, topographic variations, and advective terms effects resulting in important vertical pumping) and the upwelling east of Cape Three Points (which is principally induced by local winds). In addition to recent work ruling out the role of eddies, this study clarifies the processes responsible for this coastal upwelling. specialized UPWELLING COURANT COTIER PRODUCTION PRIMAIRE CIRCULATION OCEANIQUE VARIATION SAISONNIERE MODELISATION ATLANTIQUE GOLFE DE GUINEE ZONE TROPICALE COTE D'IVOIRE 032DYNEAU Journal of Physical Oceanography 47 6 1367-1387 2017 0022-3670 https://www.documentation.ird.fr/hor/fdi:010070175 10.1175/JPO-D-16-0126.1 0022-3670 [F B010070175] https://www.documentation.ird.fr/hor/fdi:010070175 https://www.documentation.ird.fr/intranet/publi/depot/2017-07-24/010070175.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2017-07-18 2023-07-11 fdi:010070175 fre