数字地形分析技术在分布式水文建模中的应用

论述了在栅格数字高程模型（DEM）的基础上,利用数字地形分析技术来完成地形评价、河网指示、流域分割、子流域参数化等项工作的理论与方法。并结合江西潋水河流域的实际工作进行了详细的说明。研究结果表明,通过数字地形分析的方法,利用栅格DEM实现流域离散化并从中提取分布式水文模型所需要的输入参数是一种行之有效的手段。

APPLICATION OF DIGITAL TERRAIN ANALYSIS TECHNOLOGY FOR DISTRIBUTED HYDROLOGICAL MODELLING

Topography is important to the description, quantification and interpretation of many biosphere processes.  Examples of such processes in the field of hydrology include: surface runoff and water storage, energy fluxes, evapo-transpiration, soil erosion and snow metamorphosis.  Extracting topographic information for a watershed by traditional, manual techniques can be a tedious, time consuming, subjective, and error-prone task, particularly for large watersheds.
    Research over the past decades has demonstrated the feasibility of extracting topographic information directly from raster Digital elevation models (DEM) through digital terrain analysis technologies. In the field of distributed hydrological modelling, automated evaluation of DEMs has focused on watershed segmentation, definition of drainage divides and identification of the drainage networks. This automated extraction of network and subwatershed properties from DEMs represents a convenient and rapid way to parameterize a watershed. This techniques also have the advantage of generating digital data that can be readily managed and analyzed by Geographic Information Systems (GIS) ,and the extracted topographic features also can be directly input for hydrological models.
Based on our research work of NSFC Program “Integration and Systematization of Mathematic Models for Soil and Water Resource Study in a Basin and Its Application”, the paper analyzed the methods of the digital terrain analysis technologies to watershed distributed hydrological modeling. A raster digital elevation models of Lianshui Basin is used to define surface drainage, extract the drainage networks, subdivide the whole watershed into 79 subbasins, and calculate representative subbasin parameters. The D8 and burn-in methods are mainly introduced. The result show that the drainage network and subbasins extracted from DEM are acceptable as compared with that of manual digitizations from 1∶100000 topography map. All these research  works provide a solid foundation for further development of distributed hydrological modeling.