用雨量和雨强计算次降雨侵蚀力

降雨侵蚀力反映由降雨引起土壤侵蚀的潜在能力 ,是定量预报土壤流失的重要因子。降雨动能与最大 30min雨强的乘积EI30 是最常用的降雨侵蚀力指标 ,但计算复杂 ,且资料难以获得。本文从利用易获取的气象资料计算降雨侵蚀力出发 ,通过对全国 13个代表性小区侵蚀资料和 12个气象站降雨资料的分析 ,确定我国降雨侵蚀力指标为雨量和最大 10min雨强的乘积PI10 ,其精度与常用的侵蚀力指标EI30 相当。为方便对比分析并统一单位 ,进一步建立了指标PI10 与EI30 的转换关系 :(EI30 ) =0 1773(PI10 )。这样可充分利用覆盖全国的气象站整编资料 ,计算全国降雨侵蚀力 ,为水土保持规划服务

Estimation of rainfall erosivity using rainfall amount and rainfall intensity

Rainfall erosivity shows the potential ability of the soil loss caused by rainfall and is very important for predicting soil loss quantitatively.It is estimated by the product of the rainfall energy and maximum 30 minute rainfall intensity, which combined the effects of soil detachment by the raindrops on the soil surface and runoff transportation. This study is to determine the rainfall erosivity index used in China for plotting isoerodent map accurately by using detailed available weather station data.Data of rainfall and soil loss for 12 plots representing the main climate zones in China and rainfall data from 14 weather stations were used to analyze the relationship between rainfall characteristics and soil loss in different regions. The rainfall erosivity index used in China was determined to be PI 10 , where P is the rainfall amount and I 10 is the maximum 10-minute rainfall intensity. To keep the unit identical and the result comparable, the relationship for transferring from PI 10 into EI 30 were formulated:(EI 30 ) = 0.1773(PI 10 ).