結合數值天氣預報先進環流模式模擬環台暴潮水位

Abstract

近年來面對大自然颱洪災害，氣象模擬結果如何利用提供水理適當且合宜之計算條件是一重要課題。而颱風低壓導致下游邊界水位抬升，將使得內水不易排出因而致災。在現今逐漸重視防災的意識下，擁有一可參考之災害預警系統，來作為決策之相關依據，是重要且必要的。 本研究嘗試將兩尺度相近之數值天氣預報模式（Weather Research and Forecasting Model，WRF）與先進環流模式（Advanced Circulation Model，ADCIRC）進行結合，並將氣象模擬所得之資料，進一步輸出提供水理可用及符合需求的資訊，再以凡那比颱風事件進行環台暴潮水位之驗證與建置，提供一個可參考之下游邊界做為災害預警系統之依據。 建置好之架構也提供了一套完整的預報機制，並實際應用於莫拉克颱風事件嘗試進行預報設計，設計中將預報場次拆分為四場，獨立對氣象進行預報，再將四場之資訊進行暴潮水位之合成與更新，以提高真實預報之合理性與準確性。

Recently flood disasters increase due to the frequent extreme rainfall conditions. The violent typhoon not only bring heavy rainfall but also cause water level rising which result in the risk of flooding. Flood prevention agencies often rely on a flood warning system on storm surge forecasting for decision making in the emergency response. Therefore, it is important to provide accurate weather data, such as air pressures and wind velocities, for the simulation of storm surge modeling. The Weather Research and Forecasting Model (WRF) and Advanced Circulation Model (ADCIRC) are simulated under the similar domain in the present study. Air pressures and wind velocities of typhoon were generated by WRF and then provided as boundary conditions of meteorological data for ADCIRC. The ADCIRC, storm surge calculation, was calibrated by typhoon FANAPI 2012. Simulated water levels are good agreement with observations in astronomical tides and surge tides. The valid model was appropriately employed to storm surge forecasting for the typhoon MORAKOT. The storm surge boundary conditions were individually forecasted by WRF Four series meteorological date of typhoon MORAKOT. In order to improve the accuracy of forecasts, the storm surge levels are averaged by the four series of storm surge levels when forecasting periods were overlapping. The results revealed that the predictions were identical with observed date.