###### Abstract  
Typhoons Soudelor (2015) and Dujuan (2015) were two of the strongest storms to affect the Taiwan Strait in 2015. This study investigated the response of the waters on the western bank of the Taiwan Strait to the passage of Soudelor and Dujuan. This included an investigation of the resonant coupling between the tide and storm surge, typhoon wave variation caused by the storm tide, and wave-induced water level rise. Analyses conducted using numerical model simulations and observations from tidal stations and buoys, obtained during the passage of both Soudelor and Dujuan, revealed that resonant coupling between the astronomical tide and storm surge in the Taiwan Strait was prominent, which resulted in tidal period oscillation on the storm surge and reduced tidal range. The tide wave arrived earlier than the predicted astronomical tide because of the existence of the storm surge, which was attributable to acceleration of the tidal wave caused by the water level rise. Wave height observations showed that the storm tide predominantly affected the waves, which resulted in wave heights that oscillated within the tidal period. Numerical experiments indicated that both the current and the water level affected wave height. Waves were affected mainly by the current in the middle of the Taiwan Strait, but mostly by water level when the water level was comparable with water depth. Wave setup simulations revealed that wave setup also oscillated within the tidal period, and that local bathymetry was the most important influencing factor of wave setup distribution. y 2020  
The interaction between tide and storm surge has been studied since the 1980s. Both [PERSON] [2] and [PERSON] and [PERSON] [3] analyzed tidal observations and concluded that increased water depth attributable to storm surge induces acceleration of tidal wave propagation. [PERSON] and [PERSON] [4] reported that storm surge is inversely proportional to water depth and tide, and that coupling of storm surge and tides is inevitable in coastal areas with shallow water depth and large tides. Based on study of the interaction between tides and storm surges using numerical simulations and observations, [PERSON] and [PERSON] [5] concluded that nonlinear bottom stress is an important factor. [PERSON] et al. [6] studied tide-surge interaction in the Taiwan Strait during the passage of Typhoon Dan (1999). They found that tide-surge interaction in the northern portion of the Taiwan Strait is intensified by the features of the strait, and that nonlinear bottom stress is an important factor that must be considered when predicting the oscillation due to tide-surge interaction. The interaction between typhoon-induced waves and sea level elevation induced by tides and storm surges has been studied previously. According to [PERSON] [2], the effect of tides and surges on waves must be considered in coastal areas because wave height is controlled largely by water depth, and because waves contribute to the total water level by means of the wave setup through wave radiation stress. Based on investigation of wave-tide interaction in the Yellow and East China seas, [PERSON] [7] concluded that tides were the most influential factor with regard to modulation of regional mean wave characteristics. According to the findings of [PERSON] et al. [8] in relation to the east coast of Taiwan, [PERSON] et al. [9] with regard to Tampa Bay (Florida, USA), and [PERSON] et al. [10] in relation to the Bay of Biscay, waves should not be neglected in storm surge modeling in areas where large wave heights occur and the sea bottom slope is steep. The objective of this study was to investigate the response of the water of the Taiwan Strait (primarily on the western bank) to interactions among tides, storm surges, and typhoon-induced waves during the passage of typhoons Soudelor and Dujuan. A state-of-the-art unstructured grid storm surge-wave-tide coupled model was applied to simulate typhoon-induced storm surges for Soudelor and Dujuan.