The Seasonal Upwelling in the Gulf of Guinea Due to Remote Forcing

Abstract

A linear model on an equatorial ? plane is integrated over a 120-day period in a basin that approximates the tropical Atlantic Ocean. An increase in the westward wind stress of 0.025 N m?2 in the western Atlantic excites an equatorially trapped Kelvin wave that propagates eastward along the equator, moves poleward at the eastern boundary, and produces upwelling throughout the Gulf of Guinea. Cases that study the effects of nonlinearities and the inclusion of a northward wind stress are included. Nonlinearities are shown to have the effect of amplifying the effects of the Kelvin wave and prolonging the upwelling event. The inclusion of a southerly wind stress in the eastern basin provides a secondary mechanism for upwelling south of the equator along the eastern basin. Local winds. cannot account for the seasonal upwelling in the Gulf of Guinea. The simple baroclinic ocean model is integrated from rest. The effects of mean currents and bottom topography are not considered in detail.