Ocean surface winds retrieved from marine radar-image sequences

A new method for wind-field retrieval with spatially and temporally high-resolution using marine radar-image sequences is presented. The method is based on analyzing the movement of wind gusts, which become visible in radar image sequences after filtering. In contrast to previous methods, this new technique requires no calibration phase of the radar system. The retrieved wind directions are compared to wind directions of the recently developed method, were wind directions are extracted from wind induced streaks that are orientated in wind direction. Wind speeds are derived from the backscatter of temporal integrated radar-image sequences using a empirical model function, which was parameterized by training a Neural Network. The different methods are applied to radar image sequences acquired by a marine X-band radar mounted aboard an offshore platform in the North Sea. The radar derived winds from more than 1300 radar-image sequences are compared to in-situ wind data measured at the platform. In contrast to traditional offshore wind sensors, the retrieval of the wind field 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