全球暖化對台灣地區降雨特性之影響

Abstract

近年來由於全球及區域性之氣候改變，為審慎評估全球氣候變遷可能造成之衝擊及相關調適策略，本研究主要分兩部份針對全台及曾文溪流域之測站，分別取1961~2010年及近20幾年之時雨量資料作分析，第一部份將歷年之降雨資料依月分切成鋒面雨、梅雨、對流雨、颱風雨，並分析四種降雨事件之特性包括年事件發生次數、事件平均延時、事件最大延時、事件延時標準差、事件平均降雨量、事件最大降雨量、事件平均降雨強度、事件最大降雨強度，對應全球平均溫度繪製關係圖。結果顯示若全球平均溫度持續上升，則未來台灣於非夏季節之降雨次數將會減少。 第二階段針對四種降雨事件分別使用MWP(Mann-Whitney-Pettitt)檢定、Kruskal-Wallis變異數分析、Mann-Kendall趨勢檢定及累積偏差量檢定探討年降雨事件發生次數、事件平均延時、事件總降雨量及降雨事件間隔時間之平均值及變異數之變化，結果顯示台灣於非夏季節之降雨次數有減少的趨勢，而曾文溪流域颱風雨單一事件所帶來之降雨量及降雨強度皆有增加的趨勢。

Recently, it is recognized that climate change is occurring in many regions around the world due to the green house effect. In order to evaluate the impact under global climate change and management strategies, we divide the rainfall data of Taiwan and Zengwun basin into two parts. First part of the research, all rainfall data is divided into 4 different rainfall types : frontal rain, Mei-Yu, convective storm and typhoon from 1961 to 2010 and more than recently 20 years, respectively. Then analyzing the characteristics of the 4 rainfall types. The characteristics of rainfall include the frequency of annual rainfall, the average duration, the maximum duration, the standard deviation of duration, the average rainfall, the maximum rainfall, the average intensity, and maximum intensity. The relation between the characteristics of rainfall events and the global average temperature shows that if the global average temperature continues to increase, the rainfall frequency in Taiwan would be decreasing out of summer. Another part including Mann-Whitney-Pettitt (MWP), Kruskal-Wallis(KW) variance analysis, Mann-Kendall(MK) rank correlation, and Cumulative deviation (CD) methods were employed to test the average and variance of trend existences in frequency of annual rainfall, average duration, maximum duration, standard deviation of duration, average rainfall, maximum rainfall, average intensity , maximum intensity of rainfall event. The results of the study reveal that the rainfall frequency in Taiwan is decreasing out of summer. And the rainfall and intensity from typhoon event in Zengwun basin is increasing.