Publications des scientifiques de l'IRD

Djakouré S., Penven Pierrick, Bourlès Bernard, Koné V., Veitch J. (2017). Respective roles of the Guinea current and local winds on the coastal upwelling in the northern Gulf of Guinea. Journal of Physical Oceanography, 47 (6), p. 1367-1387. ISSN 0022-3670.

Titre du document
Respective roles of the Guinea current and local winds on the coastal upwelling in the northern Gulf of Guinea
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000403208900009
Auteurs
Djakouré S., Penven Pierrick, Bourlès Bernard, Koné V., Veitch J.
Source
Journal of Physical Oceanography, 2017, 47 (6), p. 1367-1387 ISSN 0022-3670
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.
Plan de classement
Dynamique des eaux [032DYNEAU]
Descripteurs
UPWELLING ; COURANT COTIER ; PRODUCTION PRIMAIRE ; CIRCULATION OCEANIQUE ; VARIATION SAISONNIERE ; MODELISATION
Description Géographique
ATLANTIQUE ; GOLFE DE GUINEE ; ZONE TROPICALE ; COTE D'IVOIRE
Localisation
Fonds IRD [F B010070175]
Identifiant IRD
fdi:010070175
Contact