径流模拟对DEM分辨率的敏感性分析

Effect of DEM's Resolution on Watershed Hydrologic Modeling

在GIS技术的支持下应用SCS模型,以黄河下游支流洛河卢氏水文站以上流域为研究区,基于1:250 000 DEM和1:1 000 000 DEM对1992-2000年的流域径流量进行了模拟,研究了径流模拟对DEM分辨率的敏感性,结果表明1:250 000 DEM的模拟值比1:1 000 000 DEM为高。由不同分辨率的DEM得到流域面积、河网结构、高程等空间参数相差较小,而坡度相关的变化较大。根据SCS模型敏感参数Cn,从坡度参数变化角度分析了不同分辨率的DEM对流域径流量影响。

With the support of GIS technology, the SCS (soil conservation service) model was selected to model runoff of the upper watershed of the Luohe River(a tributary of the Yellow River) using a 1 : 250 000 DEM and a 1 : 1 000 000 DEM. By comparison of the simulated annual average runoff yield from 1992 through to 2000, it was found that a higher runoff volume was obtained using the 1 : 250 000 DEM. There are marginal differences in area, elevation, slope, channel length, and drainage network between the DEMs of different resolution, but there is a greater difference in slope change. Through analysis of the sensitive parameter CN of the SCS model, the sensitivity of runoff modeling to DEM resolution is described from the perspective of slope change.