Upwelling around Cabo Frio, Brazil: The importance of wind stress curl

Data from the SeaWinds scatterometer on the QuikSCAT satellite are used to estimate upwelling around Cabo Frio, Brazil, due to Ekman transport and Ekman pumping. The region close to shore (up to 200 km from the coast) is characterized by negative wind stress curl (upwelling favorable) year-round, with maximum values during summer, and minimum values during fall. Integrated values from Sao Sebastiao Island to Vitoria reveal that during summer, Ekman pumping and Ekman transport are of the same magnitude in the region. Estimates of Ekman transport are relatively uniform along the coast during summer. Ekman pumping, on the other hand, is strongly enhanced between Sao Sebastiao Island and Vitoria, the region where the coldest water on satellite images is frequently found. This suggests that wind stress curl-driven upwelling is a major contributor to the coldest surface water being found near Cabo Frio.