砖红壤区降雨因子对产流产沙的影响

Effects of Rainfall Factors on Runoff and Sediment Generation in Laterite Area

应用三种无量纲化的灰色关联法分析了12个降雨因子对于砖红壤区裸地和桉林地产流的影响,以及15个降雨径流因子对于产沙的影响。结果表明:无量纲处理方法不同将导致因子关联度排序出现变化;复合因子的关联度大多数都高于单因子;与PI30相比,在砖红壤区裸地中PI5更能代表降雨侵蚀力指标,而桉林地则是PI10;Qm′H在桉林地比通用的降雨侵蚀力更适于作为坡面降雨侵蚀模型的侵蚀动力因子。研究结果将有助于建立灰色关联法在土壤侵蚀研究中的标准化程序,为建立砖红壤区土壤侵蚀预报模型提供理论支持。

By applying three dimensionless grey correlation analysis methods,effects of 12 rainfall factors on runoff generation,and then together 3more runoff factors on sediment generation were quantitatively investigated in laterite bare lands and eucalyptus forests.Results showed that with different non-dimensionalization methods,correlation ranks of these factors changed.Most combined factors rank prior to single factors.Compared with PI30 where Pis rainfall amount and I30 is rainfall density in 30 min,PI5is a proper indicator more suitable to represent rainfall-induced erosion in the laterite bare lands,and PI10 is another proper one in the case of laterite eucalyptus forests.Actually,in eucalyptus forests,prior to traditional rainfall factors,a combined factor representing runoff erosive power,denoted by Qm′H,where Qmis the peak discharge and H is runoff depth,is more suitable in hill slope soil erosion models.This study is of significance to guide an establishment of grey correlation of erosive factors and a standard procedure for soil erosion research.It also provides the theoretic support for the development of soil erosion prediction models in laterite regions.