定量降雨預報資料運用於洪水預警系統的即時操作

依據氣象局提供之定量降雨預報，臺灣地區面臨短延時強降雨，有效運用定量降雨預報於洪水預警中，實為重要課題。本研究為驗證並改善洪水水位預警模式之預報系統，利用中央氣象局劇烈天氣監測系統（Quantitative Precipitation Estimation and Segregation Using Multiple Sensor, QPESUMS）之降雨資料，整合Hydrological Engineering Center Hydrological Modelling System（HEC-HMS）與WaterSHed Systems of 1-D Stream-River Network, 2-D Overland Regime, and 3-D Subsurface Media（WASH123D）模式建立一套洪水推估系統，採用下一時刻之定量降雨預報（quantitative precipitation forecast, QPF），對於颱風及梅雨帶來的大量降水有較高的準確度，藉此降低洪峰誤差，降雨量輸入模式中以模擬水位提高預報準確度。本研究為了減少因降雨量劇烈變化造成影響性，使用三種方法（R_0^1、R_(-0.5)^(0.5)、R_0^1）計算QPF之雷達降雨量，輸入至模式中模擬水位，結果顯示梯形法（R_0^1）雨量輸入所模擬之洪峰誤差為0.23m，表現皆優於本研究中所採用之其他方法。進一步評估即時校正（real-time correct, RT）對模式質量守恆之影響，模式經即時校正後河道總水量改變幅度約為0.03%～0.26%，此改變量屬可接受範圍。

關鍵字

洪水預警；定量降雨預報（QPF）；即時校正（RT）

並列摘要

According to the quantitative rainfall forecast provided by the Central Weather Bureau, Taiwan is faced with shorter duration and heavier rainfall. Effectively using quantitative rainfall forecasting in flood warning system is an important issue. In order to verify and improve the forecast system of the flood water level warning model, this study uses the rainfall data (Quantitative Precipitation Estimation and Segregation Using Multiple Sensor, QPESUMS) of the severe weather of the Central Weather Bureau, integrates Hydrological Engineering Center Hydrological Modelling System (HEC-HMS) and WaterSHed Systems of 1-D Stream-River Network, 2-D Overland Regime, and 3-D Subsurface Media (WASH123D) model to build a flood forecasting system. The quantitative precipitation forecast (QPF) at the next moment is used to estimate this system, which has high accuracy for the precipitation brought by typhoons and monsoon, thereby reducing the flood peak error. Input rainfall data into the model to simulated water level is used to improve the forecast accuracy. In this study, in order to reduce the influence caused by the drastic changes in rainfall, three methods were used to calculate the radar rainfall of QPF. The results show that the flood peak error simulated by input rainfall data into trapezoidal method (R_0^1) is 0.23 m, which is better than other methods used in this study. Then, we assess the influence of real-time correct (RT) on the conservation of mass in this model. After the model was corrected in real time, the total water volume in the river channel changed about 0.03% ~ 0.26%, which was within the acceptable range.

並列關鍵字

Flood-warning ； Quantitative precipitation forecast (QPF) ； Real-time correct (RT)

參考文獻

王靖斈、林遠見、石棟鑫、吳瑞賢，2021，〈應用雷達降雨資料與支撐向量機於洪水預報結果之修正研究〉，《中國土木水利工程學刊》，33 卷 1 期：頁 45-54。doi:10.6652/JoCICHE.202103_33(1).0005

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