基于DEM的黄土高原丘陵沟壑区沟谷网络节点研究

Research on Channel Network Nodes Based on DEM in Hill and Gully Area of the Loess Plateau

选择黄土高原3个典型地貌类型区为试验样区,基于数字高程模型(DEM)沟谷网络与沟谷网络节点自动提取技术,得到了各样区沟谷网络节点,并从地貌形态学、沟谷成因学以及水文学原理出发,对不同级别沟谷网络节点水流累积属性进行了深入分析,结合数理统计方法获得了:(1)同一沟谷系统不同分辨率沟谷网络节点水流累积量均值分级统计规律;(2)不同地貌类型样区相同分辨率沟谷网络节点水流累积量均值分级统计规律。该结论能够有效解释黄土高原丘陵沟壑区各级沟谷系统的形成机理及其空间分异规律,同时能够合理地说明沟谷系统发育与地表侵蚀、切割强度之间的相互关系。

The Loess Plateau is a region with the most serious soil erosion in China, and its most significant feature are the completely developed and extensively and densely distributed gullies. The formation of the gullies is a kind of morphological process, and also a kind of morphological erosion pattern. The gullies play an important role in redistributing the matter energy of the ecosystems in the Loess Plateau. In this paper, three typical geomorphologic regions, i.e., the Jiuyuangou, Yanchuan and Yijun in a hilly-gully region of the Loess Plateau in Shaanxi Province, are selected to be as the study areas. The gully network and gully network nodes are derived from the three areas on the basis of the technique of automatically deriving the gully network and gully network nodes by using digital elevation model (DEM), then the attributes of the accumulated runoff volumes of gully network nodes are lucubrated based on the theories of geomorphologic patterns,formation causes of the gullies and hydrology. With the method of mathematical statistics,we finally obtain the statistical laws of average values of the accumulated runoff volumes at all the gully network nodes in the same gully system with the different resolution powers and the statistical laws of average values of the accumulated runoff volumes at all the gully network nodes in the different gully systems with the same resolution powers. The results can be used to effectively reveal the formation causes of gully network systems and the spatial differentiation laws of all the gully network systems, and can also be used to reveal the mutual relations between the development of gully network systems and the intensity of ground surface erosion and dissected intensity.