Influence of local and remote wind forcing in the Gulf of Guinea

Abstract

SEQUAL/FOCAL (Seasonal equatorial Atlantic/Programme Francais Ocean et Climat dans l'Atlantique Equatorial) data are analyzed to investigate the question of the relative importance of local and remote wind forcing in the equatorial Gulf of Guinea. The difference in the timing and rate of intensification of the winds in the eastern and western equatorial Atlantic Ocean for 1983 and 1984 is used to distinguish local and remote forcing efforts. It is found that, although asymmetry of the mixed layer thermal structure in the Gulf of Guinea can be attributed to the shallow circulation driven by the local meridional wind, the rapid cooling and the formation of a sharp thermal front at the equator and a local sea surface temperature (SST) minimum just south of the equator are correlated with the shoaling of the thermocline and this in turn is attributed to the remote forcing effect of the zonal wind intensification to the west. These results provide credence for previous conclusions by Servain et al. (1982) that the Gulf of Guinea SST is more strongly correlated with wind stress in the western equatorial Atlantic Ocean.