Wind and tidal influence on water circulation in a Galician ria (NW Spain)

The wind effect on water circulation was described by means of hydrodynamic al and thermohaline measurements carried out in the ria of Pontevedra (NW S pain) from February to July 1998. The samples were measured both at an anch ored station situated in the inner parr of the ria and at other stations lo cated in the main channel. In this way, temporal and spatial events were re lated. Thermohaline variables (salinity and temperature) were used to clari fy the current patterns measured at the anchored station. It has been obser ved that there is a clear predominance of wind in the main estuary axis dir ection. The wind direction is strongly dependent on topography. Wind speeds higher than 4 ms(-1) are able to dominate the current at surface layers, e ven against tidal effect. Easterly winds force water to leave the estuary a t surface layers while westerly winds farce water to enter it. Diurnal bree zes associated with westerly winds were rarely recorded. Bottom layers were controlled by tide, except during an upwelling event. (C) 2000 Academic Pr ess.