Typhoon Wave Simulation Responses to Various Reanalysis Wind Fields and Computational Domain Sizes

Abstract

A fully coupled tide-surge-wave model was developed to study the influence of different computational domains on typhoon wave characteristics in the waters surrounding Taiwan. Three typhoons were selected as study cases: Meranti, Malakas, and Megi, which successively impacted Taiwan in September 2016. Superposition of the CFSV2 winds blended with ERA5 winds onto the tide-surge-wave model yielded optimum simulations of typhoon waves. Storm wave responses along the eastern shelf of Taiwan resulting from three typhoons were examined in four model domains. The first domain (D01) was primarily situated in the region where giant waves were generated. The second domain (D02) covered an area extending from 114° E to 130° E and 19° N to 29° N. The third domain (D03) southwardly included the entire Bashi Channel, from longitudes of 111° E to 135° E and latitudes of 18° N to 30° N. The fourth domain (D04) was the largest among the four computational domains; it extended from longitudes of 105° E to 140° E and latitudes of 15° N to 31° N. The simulated sea state responses indicated that the smaller computational domains were inadequate for typhoon-driven storm wave computation purposes, although the areas of D01 and D02 reached approximately 0.75 and 1.38 million km2, respectively, encompassing all of Taiwan Island and adjacent waters. Our results suggest that utilizing at least D03 or a larger model domain (e.g., D04) is essential to account for the remote wind effect of typhoons on wave simulations in Taiwanese waters.