Swell waves monitored by HF ocean surface radar at Tweed Heads and Bass Strait

Abstract

HF ocean surface radar is routinely used to measure surface currents and wind wave parameters over large areas of the ocean surface. The new algorithm presented here provides a fast method of extracting swell wave parameters using frequency modulation theory and is an improvement on existing wave spectrum analyses for routine swell detection. Swell parameters are produced from second-order (sideband) energy about the first-order Bragg peaks in the spectrum. The algorithm utilizes the relationship between these sidebands and the first-order to derive swell parameters including direction, height and period. The data used to develop this algorithm were collected at two sites during 2001 using COSRAD (Coastal Ocean Surface Radar). The first deployment of this study occurred during February and March, 2001, at Tweed Heads. The second deployment occurred during July, 2001, monitoring the seaward side of the entrance to Port Phillip Bay. The radar was configured here to aid in the extraction of swell wave parameters. Both locations were selected so that radar coverage would overlap directional wave buoys operated by QBP A and Port of Melbourne Corporation. These wave buoys provided validation sets for the measured swell wave parameters and the results indicate that the COSRAD HF radar is suitable for monitoring swell in the near-shore zone.