黄土高原沟壑区沟道提取时阈值范围的研究

Study on Threshold of Channel Information Extraction in Hilly Region of Loess Plateau

沟道是水文信息的基础要素,准确地提取流域中沟道信息,是水文模型的构建、流域的划分等的必要条件。目前提取沟道通常采用河网识别法,但在阈值的选择上,往往是根据不同的流域而确定,阈值的适用范围仅限于本流域。通过对黄土高原沟壑区的不同流域为例,分别选用不同分辨率的DEM,按不同阈值进行沟道提取,讨论了DEM的分辨率对沟道提取的影响,得到适用于黄土高原沟壑区提取沟道的合理阈值范围,最后根据实际沟壑密度对得到的阈值范围进行验证。研究结果表明,黄土高原沟壑区,不同流域提取的沟道,其沟壑密度具有一定的相似性。

Channel is the basic parameter of hydrologic information, the accurate extraction of channel information provides a prerequisite for the construction of hydrologic model and the classification of the river basin. At present, river network recognition method has often been used to extract channel information. However, the selection of threshold value must be changed for the different river basins. This paper takes the different watersheds in hilly regions of loess plateau as an example, selects DEM with different resolutions respectively, uses different threshold values to extract channel information, researches the effect of DEM resolution to channel information extraction, and finally verifies the threshold range based on the actually gully density. As the result, a reasonable threshold range is suggested, which is suitable for the channel information extraction in hilly regions of loess plateau. The result also indicates that the channel information extracted from different watersheds in the research area have certain similarity in their gully density.