摘要
以黄土高原南部3 ～15°缓坡耕地为对象,以彬县、永寿、西峰、黄龙、耀县、淳化149 场侵蚀性降雨为样本,研究得出本区侵蚀降雨能量最大值为2 160.42 Jm2 ,最小值为34.53 Jm2 ,平均值为331.47 Jm2 ;径流能量最大值为741.5 Jm2 ,最小值为0 .272 Jm2 ,平均值为98 .4 Jm2 。不同降雨量、降雨历时、降雨强度量级中,侵蚀能量数量特征不同;降雨能量基本与降雨量的增加呈正相关,径流能量以50 mm 降雨量为界,形成增幅大小不同2 个区间。依据降雨量、降雨强度可将降雨能量划分为低雨强中雨型、高雨强中雨型、低雨强暴雨型和低雨强特大暴雨型4 级;依据平均径流深可将径流能量划分为浅水深低能量、中水深低中能量和大水深高能量3 级。
The experimental plots were selected in the gentle slope lands (3～15°) of six counties, i.e.Bingxian,Yongshou, Xifeng,Huanglong,Yaoxian and Chunhua county where are in the south loess plateu,149 data of rainfalls producing runoff were analysed.The results showed that the maximum, mean and minimum values of erosive rainfall energy are 2 160.42,331.47,34.53 J/m 2;the maximum, mean and minimum of runoff energy were 741.5,98.4,0.272 J/m 2.The erosive energy varied because of different rainfalls, durations and densities of rainfalls.As rainfall increared rainfall energy increased,runoff energy was divided into two intervals by less than 50 mm and more than 50 mm rainfall. Based on rainfall and intensity of rainfall, rainfall energy was divided into four classes,i.e. midium rainfall with low intensity, midium rainfall with high intensity,rainstorm with low in tensity and large rainstorm with low intensity.Based on mean depth of runoff, energy of runoff was divided into three classes,i.e.Low energy in shallow water depth, midium energy in midium water depth and high energy in deep water depth.
基金
国家"九五"科技攻关项目!(编号96-004-05 -07)
