Development of a Sea-State Database in the Northwest Pacific Ocean by Long-Term Numerical Hindcast Modelling

In the Northwest Pacific zone, all the active nuclear power plants are located in coastal areas. The extreme typhoon waves, which occur in summer and autumn, pose great risks on the nuclear facilities and related coastal infrastructures. To facilitate the assessment of the impact of typhoon waves over the whole Chinese coastal line, detailed data of the sea state over this region is necessary. For this reason, a numerical sea state data base, which includes the North-West Pacific Ocean is under construction. It will range over several decades, to provide long-term wave data in this area. An oceanic wave model with a triangular mesh covering the whole Pacific Ocean has been set up by using the third generation spectral wave model TOMAWAC. The model is calibrated by comparing the simulation results over the period of January 1999 and during typhoon Muifa (1109) to buoy data. The numerical result of significant wave height (SWH) shows an excellent agreement with the oceanic buoy observations. The minimum values of the average bias between prediction and measurement is around 2–3 cm. The prediction of mean period (MP), however, is less accurate than the results of SWH. The model underestimates the mean period with amplitudes of around 0.6–1.2 s. Five different configurations of the source terms in TOMAWAC were tested during the calibration to find the best results. The comparisons show that the BAJ configuration can provide most accurate results of SWH. The predictions for configurations JKD and JWD show best results of MP. However, the SWD configuration provides the worse results for both of SWH and MP.