This study aimed to explore the feasibility of applying hydrological attributes to characterize surface runoff pathways in the process of hillslope soil erosion due to rainfall. Combined with sub-millimeter high-resolution laser scanning and computer digital image processing method, three hydrological indicators (i.e., sinuosity, gradient, and orientation) were used to investigate the changes of the surface runoff pathways on the slope of three typical southern red soils (i.e., shale (HS), and Quaternary red clay soils (HQ1 and HQ2) under simulated rainfall conditions). The results indicated that the sinuosity and orientation of the three red soils under the rainfall intensity of 1 mm/min and 2 mm/min showed an overall downward trend within the intervals of 0.82%-9.45% and 5.60%-31.44%, respectively. The gradient increased with the accumulation of rainfall and tended to be close to the slope of the test plot. Continuous rainfall increased the differentiation in runoff pathway characteristics and the greatest changes appeared at the first rainfall. Compared with HS and HQ1, the runoff pathway characteristics of HQ2 changed more consistent. Specifically the sinuosity of the first-level had the most dramatic change with the progress of rainfall. The rainfall intensities had a significant impact on the correlation between indicators. The correlation coefficients sorting with surface roughness were orientation >gradient >sinuosity. And they were significantly related to runoff under 1 mm/min rainfall intensity, while had positive correlation with sediment under 2mm/min rainfall intensity. In conclusion, there were more remarkable relationship between orientation, gradient and slope erosion under 1 mm/min rainfall intensity. This provided innovative ideas for applying the orientation and gradient to the simulation and prediction model of the rainfall erosion process in the sloping farmland in the southern red soil area.

中文翻译：

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使用水文属性表征山坡土壤侵蚀过程中的地表径流路径

本研究旨在探讨应用水文属性来表征降雨导致的山坡土壤侵蚀过程中地表径流路径的可行性。结合亚毫米高分辨率激光扫描和计算机数字图像处理方法，利用曲度、坡度和方位三个水文指标，研究了三种典型南方红壤坡面地表径流路径的变化。 （即，模拟降雨条件下的页岩 (HS) 和第四纪红粘土（HQ1 和 HQ2））。结果表明，在1 mm/min和2 mm/min的降雨强度下，三种红壤的曲折度和取向度分别在0.82%-9.45%和5.60%-31.44%的区间内总体呈下降趋势。坡度随着降雨的积累而增加，并趋于接近试验地的坡度。连续降雨增加了径流路径特征的分化，变化最大的出现在第一场降雨。与HS和HQ1相比，HQ2的径流路径特征变化更加一致。尤其是第一层的曲折度随着降雨的进展变化最为显着。降雨强度对指标间的相关性有显着影响。与表面粗糙度排序的相关系数为取向>梯度>曲率。且与1 mm/min降雨强度以下的径流显着相关，而与2 mm/min降雨强度以下的泥沙呈正相关。综上所述，1 mm/min降雨强度下，方向、坡度与坡度侵蚀的关系更为显着。这为将方向和梯度应用于南方红壤区坡耕地降雨侵蚀过程模拟预测模型提供了创新思路。