Effects of DEM horizontal resolution and methods on calculating the slope length factor in gently rolling landscapes

摘要: Abstract The USLE is used world-wide to predict soil loss on the field scale from sheet and rill erosion. slope length (L) factor derived as its topographical factor. accuracy of L determines precision estimation with USLE. Uncertainties are caused by DEM resolution choice processing algorithm. In present study we made two comparisons evaluate effects horizontal algorithm in gently sloped landscapes: one between grid cumulating method (GC) contributing area (CA) using D8 flow-routing algorithm, other among single (D8, Rho8) multiple (FD8, FRho8 DEMON) algorithms for method. comparisons, 5 m, 10 m, 25 m, 50 m 100 m a 0.88 km2 catchment lowland Northern Germany were applied. results indicate that calculated any six methods sensitive resolution, which strongly affects accuracy. With decreasing correlations LCA_Rho8 LCA_D8, LCA_FD8 increase while those DEMON do not change significantly. difference LGC_D8 LCA_D8 enlarged, differences flow CA did variation larger upslope than flat valley 5 m 10 m terrain characteristics visible DEM. also depends computation approximately half LCA. It concluded very important calculation. most suitable calculation rolling landscapes. This can be selecting accurate