Testing and calibrating parametric wave transformation models on natural beaches

Abstract

To provide coastal engineers and scientists with a detailed inter-comparison of widely used parametric wave transformation models, several models are tested and calibrated with extensive observations from 6 field experiments on barred and unbarred beaches. Using previously calibrated (“default”) values of a free parameter γ, all models predict the observations reasonably well (median root-mean-square wave height errors are between 10% and 20%) at all field sites. Model errors can be reduced by roughly 50% by tuning γ for each data record. No tuned or default model provides the best predictions for all data records or at all experiments. Tuned γ differ for the different models and experiments, but in all cases γ increases as the hyperbolic tangent of the deep-water wave height, Ho. Data from 2 experiments are used to estimate empirical, universal curves for γ based on Ho. Using the new parameterization, all models have similar accuracy, and usually show increased skill relative to using default γ.