即時淹水計算之格網解析度評估

Abstract

臺灣由於獨特的自然環境，每逢颱洪暴雨來襲時都對人民造成嚴重的淹水災害。近年來，因全球氣候變遷及極端暴雨事件快速增長，淹水預警與防災成為最重大的研究課題之一。隨著都市化及人口稠密化的程度越來越高，當淹水災害發生時往往對都市地區造成重大的災害，可見人口及經濟之精華都會區的防災管理及應變措施之重要性。 近二十年來，隨著科技發展日新月異，水文監測技術有大幅地進步，降雨量之預報精度也隨之提升。本研究使用中央氣象局的定量降水預報系統(QPESUMS system)以雷達回波預測空間中降雨的分布，利用二維淹水模式並結合數值地形高程(DTM)的地文資料，考慮都會區淹水時，水流流過建物對水流造成的阻力效應，進行都會區之淹水模擬。 本研究以高雄市為模擬區域，利用2010年造成臺灣南部嚴重淹水災害的凡那比颱風作為模擬事件，研究目的為評估三種格網解析度之淹水模擬結果，分析不同解析度大小的格網之精度與效率，找出適合高雄市區域洪水預報之模擬格網解析度，且同時兼顧其效率及精確度。

According to the unique natural environment, Taiwan confronts a severe flood damage problem in typhoon seasons. Recently, due to global climate change and extreme weather, the prediction and prevention of flood damage becomes one of the most important research issues. The highly development area and densely concentrated population result in severe damage during flood occurs. Flood management and response plan become more important in metropolitan area. In recent twenty years, the hydrological monitory and rainfall intense prediction techniques have a great progress in its accuracy. QPESUMS (Quantitative Precipitation Estimation and Segregation Using Multiple Sensors) developed by the Central Weather Bureau was applied to observe real-time Radar rainfall and its spatial distribution. DTM (Digital Terrain Model) and 2D inundation model which considers the blockage effect of buildings were applied to simulate the water depth in metropolitan area. In this study, Kaohsiung city is selected as the study area and typhoon Fanapi which makes tremendous flood damage in Southern Taiwan in 2010 is adopted as the study case. The main purpose of this study is to find the proper grid resolution of flood forecasting computations in Kaohsiung city from the evaluations of the efficiency and accuracy of three different resolutions.