Effects of DEM resolution on results of the SWIM hydrological model in the Changtaiguan basin
SWIM水文模型的DEM尺度效应

In this paper,the impacts of the Digital Elevation Model(DEM) with different resolutions on the simulation results of the SWIM hydrological model are examined for the Changtaiguan basin in the upper reaches of the Huaihe River basin in East China.Fifteen DEM resolutions(from resolution of 1000x1000 m to resolution of 30x30 m) are analyzed on their impacts on landscape parameters and runoff simulation results.Based on this,it is found that the best fitting DEM resolution in the study area is 90~120 m,and that both the ratio of Grid Area/Basin Area and the 'thousand million' formula are suitable methods.The Nash-Sutcliffe coefficients decline with DEM resolution;yet when DEM resolution is larger than 250 m,the Nash-Sutcliffe coefficients increase,because DEM grid is too coarse to display basin terrains.The simulation results of hydrological extreme events from 15 different DEM resolutions show a high variability.The high Nash-Sutcliffe coefficients do not reflect the hydrological extreme events,especially in the flood period.For the dry season,the simulation results of the 15 DEM resolutions show relatively good results.The results of the SWIM hydrological model are more sensitive to precipitation when the DEM resolution is decreasing.