即時降雨資料應用於淹水預報之研究

Abstract

台灣過去在淹水模擬與應用方面有良好的成果，但大都以配合地面雨量站之降雨分析為主。目前雨量觀測除個別的地面雨量站外，利用雷達降雨推估技術近年來已在空間及時間分佈觀測上有突破性的進展，本研究主要是利用中央氣象局研發的QPESUMS整合雷達觀測降雨系統資料，做為流域淹水計算之用。 本研究利用二維漫地流淹水模式配合QPESUMS提供之雨量資訊，其資料格式時間間距為10分鐘、空間解析度約1.25公里。淹水模式採用解析度1.2公里的淹水計算網格，主要目的在於即時演算淹水模擬結果，做為預測流域空間未來可能發生淹水之地區及颱洪應變作業之參考。 研究區域選定八掌溪流域，使用2005年6月12日暴雨及海棠颱風兩場事件的雨量資料，完成數值模擬且比較淹水模擬範圍，模式在短時間內可完成淹水計算工作。本研究有助於研判淹水地區及進行淹水預警。

The performance of application on the numerical models in inundation simulations was fine in Taiwan, but most of the models made use of the rainfall data from the rain-gauge stations. In this study, the precipitation data was obtained not only from traditional rain-gauge stations but also from the modern precipitation radar which was a progressive detection system in space and time in recent years. By use of QPESUMS ( Quantitative Precipitation Estimation and Segregation Using Multiple Sensors ) , constructed and developed by the Central Weather Bureau, this study arms to predict inundation range and depth in a watershed using the numerical model with the radar precipitation observation system. The precipitation data with an approximately 1.25km spatial resolution is used for the two-dimensional overland inundation model. The inundation model using 1.2km×1.2km in computational grid and ten minutes in time step provided by QPESUMS calculates immediately so as to predict the possible flooded areas in the watershed. The results can be use for typhoon emergency response. The research area is the Ba-zhang Creek Basin. The precipitation data from two events, the storm on June 12, 2005 and typhoon Haitang were simulated for model verification. The simulated results from above events were compared with the field observations. These calculations of the inundation simulations can be completed in a short period of time so that the numerical model can be used to predict inundated areas for flood warning in advance.