High-resolution atlas of extreme wave height and relative risk ratio for US coastal regions

Abstract

Interest in marine energy development has motivated numerous studies on extreme wave conditions to characterize wave loads and project risks. Metrics on extreme wave conditions, including extreme wave height, are limited in nearshore regions by insufficient spatiotemporal coverage and resolution of wave data. This study estimates 1-, 5- and 50-year return period significant wave heights, and relative-risk-ratios computed by non-dimensionalizing these extreme wave heights with their mean values, for US nearshore regions using 32-year regional SWAN wave hindcasts with spatial resolutions of 200–300 m. The model-derived extreme wave height estimates are systematically biased lower than buoy-derived estimates, but are well correlated enabling simple bias correction to buoy-observations. As wave heights at shallow nearshore sites are physically limited by depth-induced wave breaking, model-derived extreme wave height estimates are replaced with estimates using common empirical models based on breaking depth limits. The corrected high-resolution extreme wave height and relative risk ratio atlas generated herein provides important metrics that support resource characterization for the marine energy industry, including resource and site assessment, and the establishment of upper design limits for device type classification and certification to streamline product line development.