台灣降雨特性變化及降雨沖蝕指數圖修訂

Variations of Rainfall Characteristics and Revision of Rainfall Erosivity Map in Taiwan

蘇志強(Chih-Chiang Su) ； 吳佩儒(Pei-Ju Wu) ； 盧昭堯(Jau-Yau Lu)

《中華水土保持學報》 47卷1期 (2016/03) Pp. 1-12

https://doi.org/10.29417/JCSWC.201603_47(1).0001

摘要

台灣山地廣泛且地質脆弱，汛期降雨常導致土壤沖蝕，欲應用USLE、RUSLE 及TUSLE 等公式合理推估土壤流失量，須探討各地降雨沖蝕指數因子。本文就全台10 氣候分區，分析代表測站歷年 (1975-2014)原始降雨紀錄紙、逐時與逐日降雨紀錄，得知有效降雨最大30 分鐘與最大60 分鐘降雨強度關係頗佳，然受地域性、季風及颱風路徑影響，仍有一定之變異性，其比值介於1.22-1.55。經探討全球暖化降雨特性變化，推導近年 (2001-2014) 年降雨量與年降雨沖蝕指數關係式，應用全台339 自記雨量站，修訂年等降雨沖蝕指數圖，可供氣候變遷下水土保持規劃之參考。

關鍵字

有效降雨量 ； 降雨沖蝕指數 ； 最大30 分鐘降雨強度 (I_(30)) ； 最大60 分鐘降雨強度 (I_(60)) ； 年等降雨沖蝕指數圖

並列摘要

Taiwan is a mountainous island with frail geology. It often has severe soil erosion during the rainy season. In order to reasonably estimate the amount of soil erosion with equations such as USLE, RUSLE andTUSLE, it is necessary to investigate the regional variations of the rainfall erosion index (R). In this study, ten climate regions were identified, and their raw rainfall recording sheets, and hourly and daily rainfall records were analyzed between 1975 and 2014. The results indicate that the maximum 30-min rainfall intensity (I_(30)) and the maximum 60-min rainfall intensity (I_(60)) are highly correlated in effective rainfall events. Also, we found significant regional and monsoon and typhoon route effects. The ratio of I_(30)/I_(60) ranged from 1.22 to 1.55. Moreover, the variations of rainfall characteristics caused by global warming were investigated. The relationships between annual rainfall and rainfall erosion index for 10 representative stations were derived for recent years (2001-2014), and applied to 339 precipitation recording stations. Accordingly, the Taiwan annual rainfall erosivity map was revised. The revised map can be used for soil and water conservation planning.

並列關鍵字

Effective rainfall amount ； Rainfall erosion index ； Maximum 30-min rainfall intensity (I_(30)) ； Maximum 60-min rainfall intensity (I_(60)) ； Rainfall erosivity map