| Abstract: | 侵台颱風雨、梅雨、地形雨和對流雨常會造成財產的損失和人員的傷 亡，付出的社會成本也相對的提高。為了解台灣地區近四十年（1958~年 ）降水的變動情形與自然因子中准兩年週期（QBO；Quasi-Biennial Oscillation）、艾尼紐/南方振盪（ENSO；EI Nino/Southern Oscillation）以及太陽黑子（Sunspot）週期的關係，人為因子中溫室效 應（Global Warming）以及熱島效應（Heat Island）對台灣降水的影響 ，故選取十三個測站（彭佳嶼、基隆、宜蘭、台北、新竹、台中、澎湖、 阿里山、玉山、台南、恆春、台東、花蓮），利用統計上的變方分析（ Analysis of Variance）、裂區設計（Split Plot Design）、時間序列 迴歸分析（Time Series Regression）、頻譜分析（Spectral Analysis ）、交叉頻譜分析（Cross-spectral Analysis）加以探討其變化的型態 、趨勢、週期，以了解1958年以來台灣地區降水的變化情形。 研究結 果發現:侵台颱風雨、梅雨、對流雨和地形雨降水皆反應出受到平流層擾 動、艾尼紐事件的影響。就空間而言:近40年來對流雨和地形雨在各地的 差異程度最大，侵台颱風挾帶雨、梅雨都有其相似的地域性存在。就時間 而言:將1960~1995年降水平均分成三期，大部分測站梅雨期、對流雨和地 形雨（1972~1983年）的平均降水量較近40年平均值高，梅雨期降水以台 灣中部地帶變動幅度較大。研究結果顯示:1958年以來侵台颱風挾帶雨量 除台灣東部增加外，其餘皆呈減少的現象，尤其以山區的阿里山減少最多 。對流雨與地形雨除了山區（玉山）、東部（台東、花蓮）外，皆呈增加 的現象。梅雨除北端（台北、基隆）外，玉山以北有下降的現象，但玉山 以南呈上升現象。
Much property damage and loss of life, as well as social cost borne by the entire country, is caused by the heavy rains from typhoons, plum rain monsoon, and orographic and convective rain which invade Taiwan. This study analyzes the rainfall in various regions of Taiwan in the last 40 years (1958-1995) in order to understand the relationship between the changes and natural factors including QBO（Quasi-Biennial Oscillation）, ENSO (El Nino/Southern Oscillation), the sunspot cycle, and man- made factors of global warming and the local heat island effect. Thirteen stations'''' (see note) records were selected for statistical analysis including variance, split plot design, time series regression, spectral analysis, and cross-spectral analysis, in order to discuss the type, trend, and period of change in Taiwan regional rainfall since 1958. The results include: typhoon, plum monsoon, convective and orographic rain all respond to tropospheric disturbances and ENSO events. By location, in the last 40 years convective and orographic rain show the greatest change, and typhoon and plum monsoon rains show similar geographical distribution. By time, at most stations the plum monsoon, convective, and orographic rainfall for 1972-83 was higher than the 40-year average. with the greatest change in central Taiwan plum monsoon rains. Research results indicate that since 1958 typhoon rain has increased only in eastern Taiwan, while all other regions showed a decrease, with the greatest decrease in the mountain region of Alishan. Convective and orographic rainfall both show an increasing trend except for the mountain region of Yushan and the eastern regions of Taitung and Hualien. Plum monsoon rain shows a decrease north of Yushan except in Taipei and Keelung, and a decrease south of Yushan. |
