An evaluation of the OSCR HF radar system for ocean wave measurement

OSCR (developed by the UK SERC Rutherford/Appleton Laboratory and MAREX/Marconi and now supplied and supported by Marconi Radar Co.) is a short range (from 1 to 40 km offshore) high resolution (1 km) HF radar system developed for coastal current measurement. It is also available at a VHF frequency providing shorter range but higher spatial resolution (250 m). This paper describes progress that has been made in evaluating the potential for ocean wave measurement with the HF system. Wave measurement requires better signal to noise than current measurement and a considerably more complex inversion process. The inversion algorithm used in the work presented provides measurements of the full directional spectrum at frequencies less than about 0.38 Hz. Different methods are used to extract important parameters from these spectre. The OSCR system was deployed on the North-East coast of England in the Holderness region (an area subject to severe coastal erosion) during the winter of 1995/6. The paper presents results from this deployment and includes comparisons of parameters of the directional spectrum with wave-buoy data. The results show that HF radar systems of the OSCR type have enormous potential to provide high spatial and temporal resolution wave measurements in coastal waters. Limitations to measurements, for example current variability and antenna sidelobe effects, are identified and discussed.