Modeling the residual circulation of a coastal embayment affected by wind-driven upwelling: Circulation of the Ría de Vigo (NW Spain)

The barotropic and baroclinic nontidal circulations of the Ría de Vigo (NW Spain) are studied using the three-dimensional finite difference model HAMSOM (Hamburg Shelf Ocean Model). The external forcing acting on the system includes winds, freshwater inflow in the inner part of the ria and all over its surface, and heat exchange with the atmosphere. Modeled velocity is compared with data from an AANDERAA DCM12 acoustic Doppler current meter at one site of the ria, and predicted salinity and temperature fields contrasted with SEABIRD conductivity-temperature-depth data along the main channel of the ria. All predicted current, salinity, and temperature fields are in good agreement with experimental data. A new residual circulation pattern of the Ría de Vigo and its dependence on coastal winds is described. According to this pattern the typical estuarine two-layer circulation overlays in the outer part of the ria with a lateral circulation, resulting in a three-dimensional dynamics. The lateral circulation is induced by interaction between the southward (northward) alongshore coastal jet associated with upwelling (downwelling) winds and the topographic configuration of the ria.