Eddies in the Red Sea as seen by satellite SAR imagery

We present the results of our observations of mesoscale and sub-mesoscale eddies in the Red Sea based on synthetic aperture radar (SAR) imagery. The dataset used includes about 500 Envisat Advanced SAR (ASAR) images obtained in 2006-2011 over the Red Sea. We found more than 1000 sub-mesoscale eddies, which manifest in the SAR imagery both due to surfactant films (“black” eddies) and wave/current interactions (“white” eddies), depending on the local wind speed. Sub-mesoscale eddies in the Red Sea seem to be more innumerous than in other inner seas, presumably due to a relatively deep upper mixed layer in this basin. Moreover, more than 50 meso- and basin-scale eddies were found, whose rotation was mostly anti-cyclonic and whose diameters ranged up to approx. 200 km. Most of the basin-scale eddies were found between 21°N and 24°N, which is in agreement with earlier observations and with numerical modeling.