辽河流域降雨侵蚀力的时空变化分析

降雨侵蚀力是反映流域降雨侵蚀能力的综合指标之一。根据辽河流域10个气象站的日降雨量资料，利用日降雨侵蚀力模型估算辽河流域的降雨侵蚀力。结果表明：辽河流域降雨侵蚀力的空间变异与降雨量的空间分布趋势基本一致，由东南向西北递减，变化于1000—3800MJ·mm／（hm^2·h·a）之间；降雨侵蚀力年内集中度高，6—8月3个月约占全年的80％；降雨侵蚀力年际变化大，年际变率Cv在0．367—0．649之间，采用时序系列的Mann—Kendall检验表明，降雨侵蚀力并无显著变化趋势；特别是在流域水土流失严重的西辽河地区，年降雨侵蚀力较小，但年内集中程度大，年际变化更突出。

Spatial-temporal varieities of rainfall erosivity in the Liaohe River Basin

Rainfall erosivity is an index of erosion ability of rainfall.With the daily rainfall data of ten meteorological sites in Liaohe River Basin,we estimated the rainfall erosivity and analyzed the spatial and temporal variability in the Liaohe River Basin by using the daily rainfall erosivity model.The results showed that the spatial characteristic of rainfall erosivity is consistent with the spatial distribution of rainfall,declining from southeast to northwest and varying from 1 000 to 3 800 MJ·mm/(hm²·h·a).The season distribution of rainfall erosivity is centralized and that in June,July,Augest occupy 80% of the whole year.The inter-annual variation is large,and C_v is between 0.367 and 0.649,but the result of Mann-Kendall test showed there is no significant trends of variation.Especially,in the basin of West-Liaohe River Basin where the soil erosionis most serious,the rainfall erosivity is comparatively low,although the rainfall erosivity is more concerted and varies much more between years.