Swell Prediction for the Korean Coast

Abstract

The accurate prediction of abnormally high waves occurring in the East Sea during winter is important in terms of the prevention of coastal disasters along the east Korean coast. This study attempts to hindcast the abnormally high swell wave events that occurred in October 2006 and February 2008 using the unstructured grid wave model UnSWAN with high-resolution reanalysis data from the European Centre for Medium-Range Weather Forecasts as meteorological inputs. The model used in this study incorporates an additional weighting factor for the relative wave-number in dissipation source term to improve swell propagation and wave period. Wave heights and periods are well reproduced compared with the observational data. Examination of the meteorological data and model results shows that the abnormally high waves in October 2006 were induced by the overlap of a swell wave and a wind-generated wave with nearly the same heading directions; the wave generated in February 2008 was, however, induced by the swell that propagated over very long distances from the northeastern area of the East (Japan) Sea due to enhanced atmospheric low pressure. Use of the reanalysis meteorological data and a wave model equipped with a weighting factor is found to be useful in identifying the generation mechanisms as well as reasonable estimates of abnormally high wave events.