Wind influence on water exchange between the ria of Ferrol (NW Spain) and the shelf

Abstract

The wind-induced water exchange between the ria of Ferrol (NW Spain) and the adjacent shelf is analyzed by means of a threedimensional hydrodynamic model (MOHID2000). Since thermohaline measurements indicate that the estuary can be considered vertically homogeneous a barotropic version of the model has been used. Real in situ wind measurements have been used for model calibration and further analysis. The approach to study the wind effect on water exchange through the ria strait consisted in subtracting the signal calculated with only tidal forcing (Ts) from the one with wind and tidal forcing (WTs). This shows the existence of a residual circulation, with water flowing in wind direction along surfaces layers and a counter current flowing in the opposite direction at bottom layers. The flux across the strait of Ferrol has shown to increase linearly on wind strength, with a correlation larger than 96% and reaching values close to 20 m3 s 1 under real wind forcing.