Evaluation of the seasonal variations in the residual circulation in the Ria of Vigo (NW Spain) by means of a 3D Baroclinic model

Abstract

A 3D baroclinic model has been applied to study residual circulation in the Rı´a of Vigo (NW Spain) under different seasonal conditions. Winter, spring and non-upwelling summer conditions have been simulated. The use of a 3D model allows the spatial structure of residual circulation to be studied, both horizontaly and verticaly, and the combined effects of bathymetry, freshwater runoff, etc. to be monitored. A two-layered circulation was obtained in all situations, which is in good agreement with the partially-mixed condition of the estuary. This circulation is enhanced with increasing freshwater runoff, while its decrease makes the pattern not to be observed in the outermost part of the Rı´a. The zero residual current level depth has been estimated in all the situations, and the results have been compared to those obtained in the same conditions with a box model, finding a good agreement