Liu Chun-li, Yang Qin-ke, Xie Hong-xia
Shandong University at Weihai, Weihai 264209, China.
Huan Jing Ke Xue. 2010 Apr;31(4):850-7.
Rainfall erosivity (R) is a measure of effects of the rainfall factor on the potential capacity for soil water erosion. The characteristic of spatial and temporal of R value is the basis for soil erosion prediction. The spatial and temporal distributions of rainfall erosivity were analyzed using daily rainfall data collected between 1980 and 2003 from 22 rainfall stations located across the Yanhe River Basin. The results showed that the seasonal distribution of R values formed a single peak, concentrated between May and September and accounted for 91.61% of the total annual R value. The changes in annual average rainfall erosivity followed a similar trend to those for the annual average rainfall and erosive rainfall. The average annual R value was 1580.58 MJ x mm x (hm2 x h x a)(-1), the maximum annual rainfall erosivity (1981) was 2417.70 MJ x mm x (hm2 x h x a)(-1) and the minimum (1999) was 585.29 MJ x mm x (hm2 x h x a)(-1). The variation coefficient of annual rainfall erosivity was the medium with a value of 0.32. The annual rainfall erosivity was the greatest at the Shaofangbian station with a value of 2190.33 MJ x mm x (hm2 x h x a)(-1), while the least erosivity was found at the Liandaowan and Yangshan station with values of 1151.37 MJ x mm (hm2 x h x a)(-1) and 1146.87 MJ x mm x (hm2 x h x a)(-1), respectively. The annual average R values had a similar trend of spatial distribution with annual average erosive rainfall. The annual changes in R values increased at the rainfall stations of north, while those were found to decrease at other stations of Yanhe River Basin. Overall, the annual rainfall erosivity tended to decrease in the Yanhe River Basin with the trend coefficient value of -0.004.
降雨侵蚀力（R）是衡量降雨因素对土壤水蚀潜在能力影响的指标。R值的时空特征是土壤侵蚀预测的基础。利用1980年至2003年期间延河流域22个降雨站收集的日降雨数据，分析了降雨侵蚀力的时空分布。结果表明，R值的季节分布呈单峰型，集中在5月至9月，占全年R值的91.61%。年平均降雨侵蚀力的变化趋势与年平均降雨量和侵蚀性降雨的变化趋势相似。年平均R值为1580.58兆焦耳·毫米·（公顷·小时·年）-1，最大年降雨侵蚀力（1981年）为2417.70兆焦耳·毫米·（公顷·小时·年）-1，最小（1999年）为585.29兆焦耳·毫米·（公顷·小时·年）-1。年降雨侵蚀力的变异系数为中等，值为0.32。年降雨侵蚀力在韶方砭站最大，值为2190.33兆焦耳·毫米·（公顷·小时·年）-1，而侵蚀力最小的是连家湾站和阳山站，值分别为1151.37兆焦耳·毫米·（公顷·小时·年）-1和1146.87兆焦耳·毫米·（公顷·小时·年）-1。年平均R值与年平均侵蚀性降雨的空间分布趋势相似。R值的年变化在延河流域北部的降雨站增加，而在其他站则减少。总体而言，延河流域的年降雨侵蚀力呈下降趋势，趋势系数值为-0.004。
