Detection by ERS SAR imagery of the western alboran Gyre frontal structure (western mediterranean) during the omega-1 and FE92

摘要

We present a comparative description of the SAR imaging of the Western Alboran Gyre (Mediterranean Sea) during the fall season in the light of two in situ cruises (FE92, OMEGA-1). The SAR signature of the frontal boundaries of the gyre is compared to in situ data. Results show that influence of the atmospheric boundary layer stratification variation can explain the main backscatter variation at the front. In both cruises, a clear increase of few dB is found while crossing the front. Features of a cyclonic mesoscale eddy east of WAG are also found both in situ and SAR data. We observed that the northern part of the Alboran Sea can present surface films, while the inner water of the WAG are slick-free. In the light of our results, we suggest that there's a relation between the amount of slicks and the occurrence of upwelling and advection of Atlantic water.