Horizon / Plein textes La base de ressources documentaires de l'IRD



Publications des scientifiques de l'IRD

Kounta L., Capet X., Jouanno Julien, Kolodziejczyk N., Sow B., Gaye A. T. (2018). A model perspective on the dynamics of the shadow zone of the eastern tropical North Atlantic. Part 1 : the poleward slope currents along West Africa. Ocean Science, 14 (5), 971-997. ISSN 1812-0784

Fichier PDF disponiblehttp://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers18-09/010074013.pdf[ PDF Link ]

Lien direct chez l'éditeur doi:10.5194/os-14-971-2018

A model perspective on the dynamics of the shadow zone of the eastern tropical North Atlantic. Part 1 : the poleward slope currents along West Africa
Année de publication2018
Type de documentArticle référencé dans le Web of Science WOS:000444331100002
AuteursKounta L., Capet X., Jouanno Julien, Kolodziejczyk N., Sow B., Gaye A. T.
SourceOcean Science, 2018, 14 (5), p. 971-997. ISSN 1812-0784
RésuméThe West African seaboard is one of the upwelling sectors that has received the least attention, and in situ observations relevant to its dynamics are particularly scarce. The current system in this sector is not well known and understood, e.g., in terms of seasonal variability, across-shore structure, and forcing processes. This knowledge gap is addressed in two studies that analyze the mean seasonal cycle of an eddy-permitting numerical simulation of the tropical Atlantic. Part 1 is concerned with the circulation over the West African continental slope at the southernmost reach of the Canary Current system, between similar to 8 and 20 degrees N. The focus is on the depth range most directly implicated in the wind-driven circulation (offshore and coastal upwellings and Sverdrup transport) located above the potential density sigma(t) = 26.7 kg M-3 in the model (approx. above 250 m of depth). In this sector and for this depth range, the flow is predominantly poleward as a direct consequence of positive wind stress curl forcing, but the degree to which the magnitude of the upper ocean poleward transport reflects Sverdrup theory varies with latitude. The model poleward flow also exhibits a marked semiannual cycle with transport maxima in spring and fall. Dynamical rationalizations of these characteristics are offered in terms of wind forcing of coastal trapped waves and Rossby wave dynamics. Remote forcing by seasonal fluctuations of coastal winds in the Gulf of Guinea plays an instrumental role in the fall intensification of the poleward flow. The spring intensification appears to be related to wind fluctuations taking place at shorter distances north of the Gulf of Guinea entrance and also locally. Rossby wave activity accompanying the semiannual fluctuations of the poleward flow in the coastal waveguide varies greatly with latitude, which in turn exerts a major influence on the vertical structure of the poleward flow. Although the realism of the model West African boundary currents is difficult to determine precisely, the present in-depth investigation provides a renewed framework for future observational programs in the region.
Plan de classementLimnologie physique / Océanographie physique [032] ; Sciences fondamentales / Techniques d'analyse et de recherche [020]
LocalisationFonds IRD [F B010074013]
Identifiant IRDfdi:010074013
Lien permanenthttp://www.documentation.ird.fr/hor/fdi:010074013

Export des données

Disponibilité des documents

Télechargment fichier PDF téléchargeable

Lien sur le Web lien chez l'éditeur

Accès réservé en accès réservé

HAL en libre accès sur HAL

* PDF Link :

    à télécharger pour citer/partager ce document sur les réseaux sociaux académiques

Accès aux documents originaux :

Le FDI est labellisé CollEx

Accès direct

Bureau du chercheur

Site de la documentation

Espace intranet IST (accès réservé)

Suivi des publications IRD (accès réservé)

Mentions légales

Services Horizon

Poser une question

Consulter l'aide en ligne

Déposer une publication (accès réservé)

S'abonner au flux RSS

Voir les tableaux chronologiques et thématiques

Centres de documentation


Montpellier (centre IRD)

Montpellier (MSE)









La Paz