Spatial distribution of surface wave field in coastal regions using spaceborne synthetic aperture radar images

Abstract

An algorithm to retrieve swell wavelength and significant wave height from spaceborne synthetic aperture radar (SAR) images is used to study the spatial distribution of the surface wave field in the coastal region west of the mouth of the Columbia River. This algorithm utilizes the SAR image itself to obtain wind speed and direction needed in the retrieval process. Collocated in situ wind or scatterometer wind measurements are not needed in this retrieval. The wave parameters derived from 142 archived Standard Beam Mode Radarsat SAR images were validated with concurrent moored buoy measurements. Spatial variability of the surface wave field in the region is investigated using wave parameters derived from over 140 SAR images at three sites, and two SAR images. This study shows that the variation of swell wavelengths is consistent with linear wave dynamics as the swell propagates from deep to shallow water depths. Examination of the evolution of the significant wave heights suggests that significant differences in energy dissipation are found in the region.