贵州喀斯特地区侵蚀性次降雨产流产沙特征研究

为研究喀斯特地区侵蚀性次降雨与产流产沙特征，选取贵州省关岭县蚂蝗田小流域坡面径流小区监测资料，采用经验频率统计法、快速聚类和判别聚类法、降雨侵蚀力简易计算法进行研究。结果表明：5—9月为侵蚀降雨主要集中月份，占侵蚀降雨总量9808%，占降雨总量4883%，6月是侵蚀降雨最多的月份；喀斯特地区侵蚀性次降雨雨量和雨强标准为1449mm和151mm/h；侵蚀性次降雨划分为A （大雨量、长历时、小雨强、低频率）、B （小雨量、短历时、大雨强、高频率）、C （中雨量、中历时、中雨强、高频率） 3种降雨类型；B类型的产流产沙能力远大于A、C，是喀斯特地区最易产流产沙的降雨类型；次降雨侵蚀力R的计算公式中将PI30替换为PI后，更能反映喀斯特地区侵蚀性次降雨产沙的变化特征。

Study on the Characteristics of Single Erosive Rainfall and Runoff and Sediment Yield in Karst Area of Guizhou

The objective of this study was to study the characteristics of erosive rainfall and runoff and sediment yield in Karst area. Data were collected in a soil and water loss monitoring station in Mahuangtian of Guanling County, Guizhou province. Analyzing the data by using the empirical frequency statistics, fast clustering and discriminant clustering method, and the simple calculation method of rainfall erosivity. Results showed that erosion rainfall mainly concentrated from May to September, accounted for 9808% of the total erosive rainfall and 4883% of the total rainfall. Erosive rainfall occurred most in June. The standard of single erosive rainfall and rainfall intensity in Karst area was 1449 mm and 151 mm/h. Single erosive rainfall was divided into the following three types of rainfall, A (strong rainfall, long duration, light rain and low frequency), B (little rainfall, short duration, high rainfall intensity and high frequency) and C (medium rainfall, medium duration, medium rainfall intensity and high frequency). The runoff and sediment yield of B type was much larger than that of A and C, and also was the easiest type produced runoff and sediment in the karst area. The erosivity R of single erosive rainfall was better reflected the variation characteristics of sediment erosion in Karst area when the PI30 replaced by PI in the R calculation formula.