植被对降雨的再分配分析
Redistribution Model of Rainfall by Vegetation
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摘要: 定量分析植被对降雨的再分配过程和植被影响雨滴溅蚀的方式,并比较了它们在被分配前后的击溅侵蚀能量。植被对降雨的再分配主要有3种形式:截流、透流和干流,其中,只有透流能溅蚀地面。再分配减少了溅蚀地面的雨量,但增加了雨滴直径。经过比较,结论如下:1)枯落物覆盖度与溅蚀能量呈线性负相关,枯落物覆盖度越大,溅蚀能量越小;2)在降雨量达到透流(经枝叶聚集部分)临界雨量以后,植被高度是所有植被特性中影响溅蚀能量贡献率最大的因子,植被越高,溅蚀能量越大;3)在降雨量达到透流(经枝叶聚集部分)临界雨量以后,雨滴终速度越大,植被所能减少的溅蚀能量越多。Abstract: The process that vegetation redistributes rainfall and the way that vegetation change the raindrop' s energy were analyzed quantitatively in the paper. Then the raindrop' s energy. to splash was compared. There are 3 ways for the vegetation to redistribut the rainfall, i. e., interception, through fall and stem flow. Among them, only through fall can splash the ground. The redistribution decrease the rainfall to splash the ground, but it increases the raindrop' s diameter. Through the comparison, conclusion is obtained as follows: (1) Litter coverage is connected with the energy of splash erosion in linear negative correlation. The larger the litter coverage is, the less the energy of splash erosion is. (2) When rainfall comes up to the critical rainfall to produce throughfall (accumulated on leaf and branch), the energy of splash erosion is connected with the canopy density in linear negative correlation, but it is no correlation with the height of vegetation; after the through fall formed the height of vegetation is the most important factor. The higher the vegetation is, the more the energy of splash erosion is. (3) The larger the raindrop s diameter is, the more the energy of splash erosion which is reduced by vegetation.