水文地貌关系正确DEM的建立方法

On constructing methods of hydrologically correct DEMs

水文地貌关系正确DEM(hydrologically correct DEMs,Hc-DEM),是指符合水文地貌学基本原理,正确反映水文要素(水流方向、水流路径、水系网络、流域界线等)与地貌特征发生和位置关系的DEM。区域尺度水文和土壤侵蚀等研究中,地形因子参数只能利用DEM来提取,为了准确反映地面形态,有效提取地貌和水文特征因子,建立Hc-DEM是必需的。笔者对Hc-DEM的概念、建立方法进行了讨论和介绍;以黄土高原为例,提出了利用多种比例尺数字地形图和ANUDEM软件建立DEM的关键参数;通过与TIN方法建立的DEM的比较,对所建立的DEM进行了简要评价。研究表明,利用我国已有的数字地形图和ANUDEM软件,可以建立Hc-DEM,为流域水文和区域尺度水土流失定量分析模拟、区域尺度植被适宜性评价等研究提供更加直接的数据支持。

Hydrologically correct DEMs （Hc-DEM） is one of DEMs which correctly and sufficiently represents genesis and locational relationship between hydrologic parameters, including direction and pathway of overland runoff, stream networks, and boundary of watershed, and landform, etc. As the only way to extract terrain parameters based on DEMs for the studies of watershed hydrology, and soil erosion modeling of regional scale, therefore it is necessary to constructing Hc-DEMs for representing terrain shape, extracting terrain and hydrology parameters. In this paper, the concept, constructing method of Hc-DEMs were introduced and discussed, then taking loess Plateau as an example, key parameters for Hc-DEMs constructing based on digital topographic maps and ANUDEM software package were identified by series tests; the quality of resultant DEMs have been assessed by comparing them to DEMs from TIN approach which is widely applied in China. The results show that varied resolution Hc-DEMs can be generated based on available digital topographic maps, including features of contour, spot heights, stream lines, etc, and ANUDEM software, and provide solid support for hydrology and soil erosion modeling at the watershed/regional scales, and mapping of vegetation suitability.