石碇雨量站年最大一日、二日、三日降雨量及景美溪下游水文站年最大一日逕流量之頻率分析

Frequency Analysis of Annual One-Day, Two-Day, Three-Day Maximum Rainfall In Shiding Rain Gauge and Annual One-Day Maximum Runoff At Jingmei Downstream Hydrological Station

廖俊瑋(Chun-Wei Liao) ； 宋健豪(　Jian-How Sung) ； 詹仕堅(Shih-Chien Chan) ； 廖學誠(Shyue-Cherng Liaw)

《中華林學季刊》 47卷4期 (2014/12) Pp. 359-371

摘要

本研究以景美溪作為案例，從1970年至2009年間，針對區內石碇雨量站年最大一日、二日、三日降雨量與景美溪下游水文站年最大一日逕流量進行頻率分析，比較極端值一型分佈、對數常態分佈、皮爾森三型分佈及對數皮爾森三型分佈之適切性，並據此探討在氣候變遷情況下，近期水文特性變化之趨勢。結果顯示，年最大一日雨量及年最大一日流量均以皮爾森三型分佈為佳，至於年最大二日及三日雨量則以極端值一型分佈最優。此外，不論是降雨量或逕流量，後期（1987-2009年）的平均值及變異係數均比前期（1970-1987年）明顯增高。整體而言，景美溪集水區的年最大一日降雨量及年最大一日逕流量均逐漸增高，顯示出未來的極端水文事件將具有上升之趨勢。

關鍵字

頻率分析 ； 極端值一型 ； 皮爾森三型 ； 極端水文事件

並列摘要

The Jingmei stream was selected in this study. The annual one-day, two-day, threeday maximum rainfall in Shiding rain gauge and annual one-day maximum runoff at Jingmei downstream hydrological station during the period from 1970 to 2009 were analyzed using the frequency analysis. Four probability distributions were compared, including extreme-value type I distribution, logarithmic normal distribution, Pearson type III distribution and logarithmic Pearson type III distribution, in order to study the variation trend of hydrological characteristics under climate change condition. Results showed that the Pearson type III distribution was suitable for annual one-day maximum rainfall and runoff; while the extreme-value type I distribution was favorable for annual two-day and three-day maximum rainfall. Moreover, the mean value and coefficient of variation of observed rainfall and runoff in late stage (1987-2009) were higher than that in early stage (1970-1986). In conclusion, there was an increasing trend for the annual oneday maximum rainfall and runoff at the Jingmei stream watershed. It revealed that the occurrence probability of extreme hydrological events will be higher in the further.

並列關鍵字

Frequency analysis ； Extreme-value type I distribution ； Pearson type III distribution ； Extreme hydrological Event