A numerical study of the effects of bottom topography and coastline geometry on the Southeast Brazilian coastal upwelling

A two-layer finite element model is used to investigate the effects of bott om topography and coastline geometry on the coastal upwelling of the Southe ast Brazilian continental shelf. Three cases are analyzed: (1) real topogra phy and real coastline; (2) flat bottom and real coastline and (3) real top ography and smoothed coastline. For all the numerical simulations the model was integrated for five days using a constant northeast wind. The first ca se reproduces reasonably well the characteristics of wind-driven upwelling with respect to location and magnitude. When comparing the second and third case results with the first one, it can be seen that local bottom topograp hy and coastline geometry affect the upwelling magnitude in the whole domai n. The coastline irregularities are important in the location of the upwell ing cores in the south portion, which extends from Cabo de Sao Tome to Rio de Janeiro, primarily near Cabo Frio. Moreover bottom topography seems to b e responsible for the location of the upwelling cell in the north portion o f the domain, from Cabo de Sao Tome to Vitoria. In contrast to previous fin dings, the coastline irregularities are found to dominate over topographic variations in determining the location of Cabo Frio coastal upwelling. (C) 2001 Elsevier Science Ltd. All rights reserved.