臺灣離岸風場受颱風作用下之風浪模擬與驗證

臺灣位於易受颱風侵擾的中緯度西太平洋沿岸，對離岸風電產業而言，颱風帶來的極端風場及其對應生成之波浪大幅提升離岸風機承受的負載。本研究欲建立一高可信度的颱風風浪模擬流程，使用第三代近岸風浪模式SWAN(simulating waves nearshore)，針對臺灣竹南海洋風場(Formosa 1)之近岸海域進行颱風風浪模擬。選定2017年尼莎颱風為歷史案例分析，於模型中導入海床地形資料，並結合受廣泛使用的天氣研究與預報模式(weather research and forecasting，WRF)模擬所得颱風風場，模擬極端風況下生成之風浪。再將所得波場中的重要指標如：示性波高、週期與平均波向，與竹南海洋風場觀測塔實測資料進行比對，以驗證模擬結果準確度。結果顯示我們的模擬可捕捉大致的波場特性，示性波高的極值高估約0.5 m，週期則高估約1 s。

Taiwan is located along the mid-latitude western Pacific coastline, making it susceptible to typhoon disturbances. For the offshore wind power industry, the extreme wind fields and associated typhoon-induced wind waves can have greatly impact on the loads of offshore wind turbines. In this study, we aim to establish a framework for simulating typhoon-related wind waves with high fidelity. The third-generation model, SWAN (simulating waves nearshore), is used to simulate typhoon-induced wind waves near the coastal waters of Zhunan Meteorological Observation Tower in Taiwan. The chosen historical case study focuses on Typhoon Nesat in 2017. In the frame-work, bathymetric data is first imported into the model. The typhoon wind fields generated by the widely used Weather Research and Forecasting (WRF) model is then incorporated into SWAN to simulate extreme wave conditions. The key parameters of wave characteristics, such as significant wave height, period, and mean wave direction, are compared with actual observational data collected from the meteorological mast to validate the accuracy of our simulations. The results reveal that the key characteristics of wave fields can be largely captured in our simulations. The extreme significant height is overestimated by about 0.5 m in our model, while the period is overpredicted by about 1 s.