Numerical Simulation of Large Wave Heights from Super Typhoon Nepartak (2016) in the Eastern Waters of Taiwan

Abstract

Super Typhoon Nepartak (2016) was used for this case study because it is the most intense typhoon that made landfall in Taiwan in the past decade. Winds extracted from the Climate Forecast System version 2 (CFSV2) and ERA5 datasets and merged with a parametric typhoon model using two hybrid techniques served as the meteorological conditions for driving a coupled wave-circulation model. The computed significant wave heights were compared with the observations recorded at three wave buoys in the eastern waters of Taiwan. Model performance in terms of significant wave height was also investigated by employing the CFSV2 winds under varying spatial and temporal resolutions. The results of the numerical experiments reveal that the simulated storm wave heights tended to decrease significantly due to the lower spatial resolution of the hourly winds from the CFSV2 dataset; however, the variations in the storm wave height simulations were less sensitive to the temporal resolution of the wind field. Introducing the combination of the CFSV2 and the parametric typhoon winds greatly improved the storm wave simulations, and similar phenomena can be found in the exploitation of the ERA5 dataset blended into the parametric wind field. The overall performance of the hybrid winds derived from ERA5 was better than that from the CFSV2, especially in the outer region of Super Typhoon Nepartak (2016).

Assessment of Offshore Wave Energy Resources in Taiwan Using Long-Term Dynamically Downscaled Winds from a Third-Generation Reanalysis Product

“…A fine mesh with a resolution of approximately 200 m was distributed along the coast of Taiwan (as shown in Figure 2b) and its offshore islands (as shown in Figure 2c), while a coarse mesh with a resolution of approximately 40 km was configured in the open ocean far from the coastal zone. The fine mesh developed in the present study is able to characterize the surf zones and shallow waters [46,[48][49][50][51]. Notably, the performance of the JONSWAP spectrum in the simulation of long-term or extreme sea states in the offshore waters of Taiwan was impressive, and this spectrum has been widely used to simulate wave conditions worldwide [35][36][37][38][46][47][48]52], although the JONSWAP spectrum was originally applied in the North Sea.…”

“…Details on the coupling procedure for the SCHISM-WWM-III coupled modeling system are available in [45]. Due to its high numerical efficiency and robust matrix solver, SCHISM-WWM-III has been successfully implemented to investigate wave power resources and produce potential storm wave hazard maps for Taiwan [35,36], evaluate the wind forcing effect on storm wave hindcasting [37], quantify storm tide-induced nonlinear interactions [38], simulate extreme waves caused by a super typhoon [46,47], and evaluate wave-current interactions [48].…”

On the Sensitivity of Typhoon Wave Simulations to Tidal Elevation and Current

“…Many previous studies have indicated that reanalysis products underestimate typhoon wind speeds, especially for the far-field regions of typhoons [37][38][39][40][41][42]. The peak typhoon wind speed can be considerably improved through a superposition method by combining parametric typhoon and reanalysis winds.…”

Impact of Typhoons on Floating Offshore Wind Turbines: A Case Study of Typhoon Mangkhut

“…Typhoons are intensive ocean forces that can destroy coastal properties or offshore engineering structures, leading to significant economic losses [2]. Generally, typhooninduced waves are characterized by extreme heights [3,4], which pose a substantial threat to the stability and structural integrity of floating foundations [5][6][7].…”