The availability and accuracy of HF radar wave measurements

The possibility of measuring the ocean wave directional spectrum in real time at up to 350 locations every 10 minutes was demonstrated in the EuroROSE experiments at Fedje, Norway and Gijon, Spain in 2000. These experiments used the WERA HF radar which, at the operating frequency used, had a maximum range for wave measurements of about 20 km. Trials of the PISCES HF radar are currently underway in the UK with a view to providing real-time wave measurements to over 100 km. These and earlier experiments have clarified the main limitations to the accuracy of the wave measurements (scattering theory used, noise levels and antenna sidelobes) and the temporal variability in spatial coverage (noise levels, antenna sidelobes, waveheight and surface current variability). In this paper the accuracy and limitations will be discussed with examples given from the above mentioned experiments and also from the EU-funded SCAWVEX experiments and the ONR-funded SHOWEX experiment. Work in progress directed at solving or minimising their impact on wave measurement accuracy will be described.