颱風降雨空間特性與面積遞減關係之研究

A Study on the Relation of Spatial Characteristics of Typhoon Rainfall and Areal Reduction Factor

張家誌(Chia-Chih Chang)

指導教授 ： 虞國興

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2007年)

https://doi.org/10.6846/TKU.2007.00574

摘要

水文設計上常利用降雨強度延時頻率曲線(Intensity-Duration-Frequency Curve，簡稱IDF曲線)推求設計雨量，然而IDF僅代表單一測站的降雨特性，並不能夠充分的表現出區域空間實際之分佈情況，導致在實際應用上存在是否設計過量之疑慮。因此，希望藉由面積遞減因子(areal reduction factor, ARF)，將單站設計之點降雨量轉換成代表區域之面降雨量，以符合實際之區域雨量設計。
本研究之目的在於引入降雨空間特性函數(spatial relation function)等理論架構，建立區域之不同降雨強度、延時、頻率與面積大小之遞減關係，並配合IDF之應用，求得區域雨量。研究中，以淡水河流域為研究區域，選取流域內35個雨量站，1973年~2005年，共145場颱風之時雨量資料為分析對象，分別針對1、2、3、6、12、24、48小時等七種延時進行分析。研究中，先以某個雨量站當成點降雨中心，並逐次納入鄰近雨量站，即可分別得到不同距離下、同時間之雨量比值關係，依序置換不同雨量站為中心進行相同之分析，並利用威伯(Weibull)點繪法，進一步推求重現期距，即可建立研究區域之不同重現期距、不同延時與面積遞減關係之ARF曲線。
由研究結果可知，本研究所採用之降雨空間特性函數，可真實呈現出區域性之暴雨空間特性與面積遞減關係，而不同重現期距之暴雨所呈現出之遞減關係特性亦不相同。研究中，並提出以IDF套配ARF之設計降雨方法及建議，希冀可提供水文設計實務上之參考與應用。

關鍵字

降雨強度延時頻率曲線 ； 面積遞減因子 ； 空間特性函數 ； 威伯點繪法

並列摘要

In hydrological design, the most common approach to estimate regional design rainfall is Intensity-Duration-Frequency (IDF) relationships. Only represent this rainfall characteristic examined and stood only, can not demonstrate the regional spatial abundantly , the distribution situation of the real rainfall.They usually cause and an over-design in practical application.Therefore, hope with the areal reduction factor (ARF ), and it’s on the transformation of point rainfall to areal rainfall, the regional rainfall by corresponding to reality.
The purpose of this study, spatial relation function are used to establish the decreasing relationships between different intensities, durations, frequencies, and area sizes. Cooperate with the application of IDF, try to get the regional rainfall. The research area is Tamshui River basin, and 35 rain gauges’s 7 kinds of hourly data, 1, 2, 3, 6, 12, 24, and 48 hours, of 145 typhoons are used during 1973~2005. The first step is selecting a rain gauge as rainfall center by taking turns and adding the nearest rain gauge step by step to estimate the rainfall ratio relation of the same time with respect to the different distance separately. The last step is utilizing Weibull function can inquire into the return periods. Then, the ARF of Tamshui River basin is established.
From the result, spatial relation function of precipitation which this research institute adopts, it’s can demonstrate the regional storm spatial characteristic and decreasing relation of area. Different return periods have different decreasing relationships. Finally considering the application of this study in practice, a rainfall design method by using IDF combining with ARF will be suggested.

並列關鍵字

Intensity-Duration-Frequency Curve ； areal-reduction factor ； spatial relation- function ； Weibull function

參考文獻

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