Deriving Mesoscale Surface Current Fields from Multi-Sensor Satellite Data

Sequential multi-sensor satellite images from Envisat ASAR and WiFS are used for the computation of mesoscale surface currents in the southestern Baltic Sea (Southern Baltic Proper). Marine surface films of different origin and accumulated algae at the water surface are imaged by the sensors working in the optical, infrared, and microwave part of the electromagnetic spectrum and can thus be used as tracers for the local motion of the sea surface. Taking advantage of the sufficiently short time lags between the multiple image acquisitions (from less than one hour to one day) and of the high spatial coverage we calculated surface motion fields by enhancing and combining image-processing techniques. Our computed two-dimensional surface current fields are compared with, and they complement, existing data from numerical models.