Coherent microwave marine radar measurements of directional ocean wave spectra and mean radial current fields

Abstract

Results of measurements of ocean waves using a coherent marine radar are presented. Data were collected in a coastal environment, at the U.S. Army Corps of Engineers Field Research Facility, Duck, N.C. Measurements of ocean wave spectra derived from maps of radial components of orbital wave velocity are used to measure directional ocean wave spectra, using three-dimensional FFT algorithms. Wave height spectra can be derived directly from such measurements, without the need for a modulation transfer function (MTF) that is used for traditional marine radars. The MTF approaches can suffer from wind speed variability and wind-wave relative direction effects, and are typically robust only for equilibrium wind-wave conditions. A discussion is presented of how one might use such data to provide a real time wave profile map of the coverage area. Such a map of wave height profiles is useful in ship motion response prediction for real-time applications such as safe helicopter landings under high sea conditions.