土壤侵蚀分辨率对地形因子空间精度影响研究

Effects of soil erosion resolution on spatial accuracy of topographic factors

区域土壤侵蚀研究中,坡度、坡长等地形因子只能通过中低分辨率DEM进行提取,但是基于中低分辨率DEM提取的坡度会发生衰减,坡长会发生扩张,现有研究多是基于数理统计对这一现象进行描述,没有对其影响机理进行研究。因此,本研究将分辨率分为数据平滑和数据离散两种组分,基于中国土壤侵蚀方程对分辨率对于地形因子的空间精度的影响进行描述。研究结果表明:在统计数据方面,数据离散是影响坡长的主要因素,但是在坡长相对熵值方面,数据离散和数据平滑对于坡长都存在一定的影响,数据平滑是影响坡度的主要因素。在空间变异方面,数据离散和数据平滑均对地形因子存在影响,影响程度会随着离散和平滑程度的增加而不同。

In the study of regional soil erosion,the slope and the slope length can only be extracted by low and medium resolution DEM,but the slope of extraction will be attenuated,and the slope length will expand.Most of the existing studies describe this phenomenon based on mathematical statistics,and the mechanism of its influence is not described.In this paper,the resolution is divided into two components:data smoothing and data discretization.Based on the Chinese soil erosion equation,the spatial accuracy of the resolution for topographic factors is quantitatively described.The result shows that data dispersion is the main factor affecting slope length,and data smoothing is the main factor affecting slope,However,in terms of relative entropy of slope length,data discretization and data smoothing have some influence on slope length.In terms of spatial variation,both data dispersion and data smoothing have influence on terrain factors,of which the influence degree will vary with the increase of dispersion and smoothing degree.