Using Sar Images for Detection of a Surface Poleward Current off the West Coast of the Iberian Peninsula

The surface circulation off the western coast of the Iberian Peninsula is strongly influenced by the atmospheric pressure distribution in the North Atlantic. During the winter season, the combination of the onshore Ekman transport and the geostrophic adjustment of the large-scale oceanic zonal flow causes the appearance of a seasonal poleward along-shore flow named Navidad current. This surface flow was investigated using hydrographic data together with satellite infrared imagery. ERS Synthetic Aperture Radar (SAR) data responds to the roughness of the sea surface, and the radar backscattering strength is dominated by the Bragg backscattering mechanism. In this paper a strip of four ERS-2 SAR frames acquired over the North Atlantic ocean off the Iberian Peninsula coast on 26 November 2002 were used to try to demonstrate the capability of radar data to identify the presence of this surface current under certain hydrodynamic conditions.