A rip-current prediction/forecast model employing likelihoods of rip currents beforehand simulated by a phase-resolving wave-current model

This article addressed a new rip-current prediction model by introducing its implementation to produce a sequence of rip-current risk index. The present risk index was evaluated by using the distributions of rip-current likelihoods varied according to wave and tidal properties. The likelihoods were derived from hundreds of in-advance numerical simulations using the phase-resolving wave-current model, FUNWAVE. The numerical simulations of rip currents were conducted with various wave and tidal conditions based on possible ocean scenarios at a specific coast. The risk index can be computed by inputting ocean observations or forecasts into a function combining the distributions of rip-current likelihoods. The performance of the rip current risk index using real-time observations was checked with event snapshots of the video-monitoring records during the summer of 2021 at the Haeundae coast. As a result, it was inferred that the rip-current risk index could support appropriate and useful warning signs at most of the time when significant rip currents occurred. • A new rip current prediction model is introduced to generate a sequence of rip current risk indices. • Rip current likelihoods vary with wave and tidal conditions derived from prior FUNWAVE model simulations. • The risk index is computed by applying ocean observations or forecasts to the rip current likelihood distributions. • The rip current risk index supports appropriate warning signs in most cases when significant rip currents occur.