Re-scaling method of slope length factor in the soil erosion assessment of regional scale
Guo Weiling 1,Yang Qinke 1,2,Cheng Lin 3,Li Jun 3,Hu Jie 3*
1.Institute of Soil and Water Conservation,Chinese Academy of Sciences,Ministry of Water Resources,712100,Yangling,Shaanxi;2.College of Urban and Environment,Northwest University,710069,Xi'an;3.College of Resources and Environment,Northwest A & F University,712100,Yangling,Shaanxi:China
Abstract��
It's the only way to extract slope and slope length based on low resolution DEMs for the studies of regional scale soil erosion modeling.But the slope will reduce and the slope length will enlarge.Based on the hydrologically correct DEM of 50 m and 10 m resolution using AUNDEM software in Yan'an and its surrounding areas of Shaanxi Province with the 1��250 000 digital topographic maps and the typical area of this areas with the 1��50 000 digital topographic maps,the derived slope and slope length from 50 m resolution DEM were re-scaled to similar to the slope and slope length from 10 m resolution DEM using histogram matching principle.Then the effects of the slope and slope length of pre and post of re-scaling on soil erosion intensity was evaluated and analyzed.Results show that re-scaled slope gradient becomes steep and the re-scaled slope length becomes short with similar histograms to high resolution's slope length when this method can promises space structure steadiness.Meanwhile,four datasets of soil erosion intensity are calculated with Chinese Soil Loss Equation(CSLE),including(a) slope and slope length unre-scaling,(b)slope re-scaling,(c)slope length re-scaling,(d)slope and slope length re-scaling.Results show that the(a) can obviously increase soil erosion intensity,the(b) can decrease soil erosion intensity,but the(c) can finally increase soil erosion intensity,which can provide more accurate data support for the soil erosion assessment.
2010, Vol. 8 