Coastal dynamics off Northwest Iberia during a stormy winter period

The consequences of a stormy winter period (2009/2010) on the shelf and coastal dynamics off Northwest Iberia are analysed by using model results in combination with the set of available observations in the frame of the Iberian Margin Ocean Observatory (RAIA), a cross-border infrastructure among North Portugal and Galicia (Spain). During the study winter, the frequent arrival of weather fronts forced river plumes to flow along the inner shelf in a fast (>1 ms(-1)) jet-like structure. The buoyant current strongly influenced the outer rias, the name of the estuaries in the region, where a strong decay of surface salinity (<10.5) has been observed. Once the weather front has passed, the wind reversal forced the offshore expansion of river plumes and also the development of a winter up-welling event. Thermohaline patterns in both model and observations revealed an intrusion of warm (>15 degrees C) and salty (>35.9) waters into the rias associated with the Iberian Poleward Current. Finally, some Lagrangian modelling experiments were performed to analyse the transport ability of the plume and the effect that could have had in the biological material trapped on it. The experiments reveal that an overall northward displacement of surface particles will be expected after several alternate wind events.