Leduc-Leballeur M. auteur aut IRD de Coetlogon G. auteur aut IRD Eymard Laurence auteur aut IRD text journalArticle eng text/pdf born digital access The role of airsea interaction in the boreal spring precipitation of the West African monsoon is explored through the wind variability in the Gulf of Guinea. Linear regressions are performed in MayJune during the decade 20002009 to investigate the origin and effect of the surface wind strengthening north of the Equator. It appears that the equatorial sea-surface temperature cooling intensifies a surface-wind equatorial divergence/coastal convergence circulation, and generates a cross-equatorial pressure gradient, which both strengthen the southerlies north of the Equator. This increases subsidence above the ocean and convection in the northern Gulf of Guinea. In addition, an abrupt change is observed in the surface wind pattern in the eastern equatorial Atlantic (EEA) between April and July. To investigate the transition mechanisms, a reference date is defined as the date when the surface wind north of the Equator becomes and remains stronger than south of the Equator. Thus the maintenance of strong southerlies north of the Equator is linked to a coincident installation of a deep circulation on the whole troposphere and a northward shift of the low atmospheric local circulation. The resulting sharp seasonal transition coincides each year with a southeasterly wind burst, suggesting that the equatorial SST cooling plays a role in the precipitation along the African coast during boreal spring. specialized West African monsoon tropical Atlantic GOLFE DE GUINEE 032 139 671 387-400 2013 0035-9009 https://www.documentation.ird.fr/hor/fdi:010085714 10.1002/qj.1981 0035-9009 https://www.documentation.ird.fr/hor/fdi:010085714 https://www.documentation.ird.fr/intranet/publi/2022-07/010085714.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2013-05-31 2022-07-20 fdi:010085714 fre