Retrieval of surface-current fields and bathymetries using radar-image sequences

An algorithm for retrieving high-resolution surface-current fields and bathymetries using nautical radar-image sequences is presented. The image sequences are acquired by a common marine X-Band radar. The algorithm retrieves 3d wave-number frequency spectra for each pixel in the analyzed area. With the local 3d spectra maps of hydrographic parameters, wave spectra with its integral spectral parameters, e.g. the local significant wave height, are determined. Thereby areas of about 2 km in radius are covered by the radar. The spatial distribution of these parameters gives a better understanding of the processes near the shoreline for better application of coastal or river training measures. Especially in harbor areas and regions with coastal structures, where the wave fields are highly inhomogeneous due to shallow-water effects like refraction and shoaling as well as building effects like diffraction, is the potential of the developed method. The method is also applicable on moving vessels to get permanently information about local currents, changing water depths in near-shore regions around the ship, especially when the ship is approaching or leaving a harbor.