自然降雨条件下坡面侵蚀地表粗糙度的空间异质性

Spatial Heterogeneity of Surface Roughness of Slope Erosion Under Natural Rainfall

地表粗糙度是影响地表侵蚀的重要参数之一,也是土壤侵蚀研究的热点问题之一,研究自然降雨过程中砒砂岩区地表粗糙度的空间异质性,对其探索土壤侵蚀响应规律具有重要意义。以裸露砒砂岩为研究对象,采用地统计学和ArcGIS空间分析相结合的方法研究了坡面尺度次降雨过程下的地表粗糙度空间异质性特征。结果表明:地表粗糙度在次降雨过程中表现出中等变异性;地表粗糙度在次降雨过程中都具有较强的空间自相关性;由空间分布特征分析得出,地表粗糙度的增加量或者减少量在坡面下坡的数值变化较为明显,说明坡面的变化是坡顶被冲刷,坡底被填充;砂粒和粉粒含量均在坡下减小,而黏粒含量增大,地表粗糙度在坡下数值变化较明显,因此,地表粗糙度的变化随着土壤黏粒的变化而变化;降雨前后土壤黏粒与地表粗糙度表现出正相关,雨后的相关性更强烈,粉粒与其关系不显著,砂粒与其呈现负相关。

Surface roughness is one of the important parameters affecting surface erosion,and it is also one of the hot issues in soil erosion research.It is of great significance to study the spatial heterogeneity of surface roughness in Feldspathic Sandstone Region during natural rainfall to explore the response law of soil erosion.In this paper,the spatial heterogeneity of surface roughness of bare Feldspathic Sandstone Region was studied by geostatistics and ArcGIS spatial analysis.The results showed that:the surface roughness showed a moderate variability during one rainfall event.The surface roughness had a strong spatial autocorrelation during one rainfall event.According to the analysis of spatial distribution characteristics,the increase or decrease of surface roughness was obvious in the downhill of the slope,indicating that the changes of the slope were that the top of the slope was scoured,and the bottom of the slope was filled.The contents of sand and silt particles were decreased,but clay increased.The surface roughness changed more obviously at the bottom slope.Therefore,the surface roughness changed with the changes of soil clay particles.Before and after rainfall,soil clay contents and surface roughness showed a positive correlation,which was more strong after rain.The relationship between silt and surface roughness was not significant,and sand and surface roughness showed a negative correlation.