A high-resolution nested WAM/SWAN wave model suite aimed at rapidlyestablishing nearshore wave forecasts as well as a climatology and returnvalues of the local wave conditions with Rapid Enviromental Assessment (REA) inmind is described. The system is targeted at regions where local wave growthand partial exposure to complex open-ocean wave conditions makes diagnosticwave modelling difficult. SWAN is set up on 500 m resolution and is nested in a 10 km version of WAM. Amodel integration of more than one year is carried out to map the spatialdistribution of the wave field. The model correlates well with wave buoyobservations (0.96) but overestimates the wave height somewhat (18%, bias 0.29m). To estimate wave height return values a much longer time series is requiredand running SWAN for such a period is unrealistic in a REA setting. Instead weestablish a direction-dependent transfer function between an already existingcoarse open-ocean hindcast dataset and the high-resolution nested SWAN model.Return values are estimated using ensemble estimates of two differentextreme-value distributions based on the full 52 years of statisticallydownscaled hindcast data. We find good agreement between downscaled wave heightand wave buoy observations. The cost of generating the statistically downscaledhindcast time series is negligible and can be redone for arbitrary locationswithin the SWAN domain, although the sectors must be carefully chosen for eachnew location. The method is found to be well suited to rapidly providing detailed waveforecasts as well as hindcasts and return values estimates of partly shelteredcoastal regions.
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