氣候變遷造成降雨特性的改變，導致通用土壤流失公式(Universal Soil Loss Equation, USLE)中的降雨沖蝕指數(Rainfall erosivity, R)亦隨之改 變，間接影響土壤沖蝕量的估算。隨著極端降雨事件發生頻率的增加，過 去所使用的降雨沖蝕指數值是否適用於現今的降雨條件，是本研究探討的 重點。本研究以高屏溪集水區為研究區域，使用研究區域內近十年 (2002~2011 年)的10 分鐘雨量資料，建立27 個雨量站之年平均降雨沖蝕指 數及年降雨沖蝕指數推估公式，並繪製年平均降雨沖蝕指數等值圖。研究 結果發現，近十幾年來研究區域內之年平均降雨沖蝕指數比過去有明顯增 大的趨勢，本研究成果可提供給相關單位作為日後使用之參考依據。

Along with the impact by climate change, it is not certain that the isoerodent map of annual rainfall erosivity index can reflect the variations at present and in the future. The map in Taiwan proposed by Huang (1979) has been used for years to assess the rainfall erosivity index (R) in USLE. The spatial variations are investigated using a dataset monitored by 27 rainfall stations (from 2002 to 2011) in Gao-ping Watershed in Taiwan. Based on the relationship analysis of yearly rainfall (P) and rainfall erosivity (R), both of the factors are highly related. The spatial analysis shows the annual mean rainfall erosivity increases from west or southwest region to east or northeast region and from plain to mountain region. The annual mean rainfall erosivity is highly related with elevation..