A quasi-biennial oscillation in the equatorial Atlantic Ocean

A quasi-biennial oscillation with features characteristic of equatorial cou pled modes is found in the equatorial Atlantic Ocean. The origins of the ph enomenon are investigated by using a coupled atmosphere-ocean general circu lation model, in which the fully coupled domain is restricted to the Tropic al Atlantic (20 degreesS-30 degreesN). The simulations capture a similar os cillation regardless of whether sea surface temperatures prescribed outside the coupled domain correspond to the observed or the climatology (i.e., la ck year-to-year variability). It is concluded that the equatorial Atlantic hosts a quasi-biennial oscillation generated by coupled atmosphere-ocean in teractions internal to the basin with little influence fi om remote events, even from El Nino/Southern Oscillation.