Rip current likelihood as a function of incident wave conditions for different bathymetries

Abstract

The likelihood of rip currents as a function of water depth (tidal level), incident wave height, period, direction, and spectral spreading in both frequency and direction is investigated with a Boussinesq numerical model (FUNWAVE) for alongshore uniform, moderately variable, and strongly variable bathymetry, providing two-dimensional probability distributions of rip-current occurrence along the coast. The simulations suggest that over strongly irregular alongshore bathymetry rip-current likelihood increases with longer wave periods and narrower directional spectra. In contrast, over more uniform alongshore bathymetry, rip current likelihood increases with shorter wave periods and broader directional spectra. The simulations suggest that as bathymetric variability increases, the effects of different incident wave fields decreases.