CASC2D-SED模型的DEM尺度效应

Scale Effects of DEM Resolution on the CASC2D-SED

DEM分辨率深刻影响着以地形为基础的分布式水文过程模拟。以砒砂岩区二老虎沟小流域一个子沟为研究对象,通过无人机航测获得研究区DEM和影像,使用ArcGIS的栅格重采样方法和水文分析工具获得2-20m范围内11种分辨率的DEM、土地利用类型数据、土壤类型数据和河网数据,将相关数据输入CASC2D-SED模型,探讨不同的DEM分辨率在高分辨率区间对水文过程模拟的影响。研究表明：1）洪峰流量和模拟径流量均随DEM分辨率的降低呈波动上升;2）在2-3m和4-20m两个DEM分辨率区间水文过程线差别较大,而在4-20m范围内水文过程线变化不大;3）DEM分辨率对模型参数有重要影响,一定的DEM分辨率区间可以共用相同的水文参数,超过这个区间则必须重新率定;4）DEM分辨率增加使水文模拟效率降低。

The accuracy of the hydrographic features extracted from DEM has profound influence on the distributed hydrological simulation based on the terrain.This paper explores the influences of DEM resolution on distributed hydrological process simulation based CASC2D-SED model in the high DEM resolution range taking a child ditch of Two Tigers Ditch in arsenic rock area as the research area.The data and parameters needed to model are obtained by UAV air survey,RS interpretation,field measurement and indoor experiment.The soil particle composition is experimentally measured by Mastersizer 3000 laser particle size analyzer based on wet dispersion measurement method.The soil organic matter content is evaluated using potassium dichromate volumetric method.Eleven kinds of resolution of DEM data,soil type,land use type data and river links within the scope of 2-20mare gained using ArcGIS grid sampling method and hydrological analysis tool.The eleven kinds of resolution data are input into CASC2D-SED model,and scale effects of DEM resolution on hydrological process simulation are reviewed.The results show that：1）Peak flow and simulated runoff increase volatility with change of DEM resolution,and have same tendency.2）The hydrographs in ranges of 2-3mand 4-20mare very different,while it has little different in the range of 4-20m.3）DEM resolution has important effects on model parameters,and the same hydrological parameters can be used in 4-20m,and the parameters needed to calibrate again without this range.4）DEM resolution increase results in the decrease of hydrological simulation efficiency.