A marine X-band radar operating at grazing incidence and horizontal polarization in transmit and receive is used to analyze the backscatter of the ocean surface in space and time. This resulted in a method, called WiRAR, for retrieving the wind vector front radar-image sequences. The method extracts local wind directions from wind induced streaks, which are visible in radar images at scales above 50 m. It is shown that the streaks are very well aligned with the mean surface wind directions. Wind speeds are derived from the RCS, by parametrization of its dependency on the wind vector, which was performed by training of a Neural Network. Recently, the research platform FINO-I has been set-up in the German Bight. This platform provides various environmental data, such as wind measurements at different heights of up to 100 m for studying the atmospheric boundary layer, as well as air-sea temperatures, humidity, and other meteorological parameters. FINO-I provides, for the first time, a broad data base for detailed investigation and validation of our methods. WiRAR is applied to radar-image sequences acquired by a marine X-band radar aboard FINO-I. Thereby different atmospheric parameters, like temperatures and humidity, were studied regarding a further improvement of WiRAR. Using this extended version of WiRAR the marine radar system continuously derives winds from radar data sets. These are compared to the in-situ wind data measured at the platform. In contrast to traditional offshore wind sensors, the retrieval of the wind vector from the backscatter of the ocean surface makes the system independent of the sensors motion and installation height and reduces the effects due to platform induced blockage and turbulence effects.
