X-Band radar derived sea surface elevation maps as input to ship motion forecasting

Nautical X-Band radars used for navigation can also be used to determine spectral and individual wave properties. The sea surface reflects the incident radar beams and wave fronts become visible as stripe like pattern of high back scatter on the radar screen. When connected to a conventional nautical X-Band radar, the Wave Monitoring System WaMoS II exploits this imaging of waves to detect full directional wave spectra and to derive statistical sea state parameters as well as surface currents. WaMoS II is continuously improved with new features being developed. In particular, the sea surface elevation maps derived by WaMoS II allow to investigate and describe the spatial and temporal development of 3D ocean surface waves. The European Joint Industry Project `On board Wave and Motion Estimator (OWME)' used this measurement technique to provide the wave information that is required to predict periods of quiescent vessel motions. A task that offers valuable support for various offshore operations like e.g. the tensioning of a tanker or the landing of a helicopter. This contribution gives an overview of the overall OWME system design showing first validation results, focusing on the method to derive wave trains using the WaMoS II system.