延河流域地貌发育阶段的定量分析

A quantitative analysis of the geomorphologic evolution in Yanhe river basin

文中选取延河流域作为研究对象,基于ArcGIS10.1与ASTER GDEM数据,提取了延河流域主要支流及其流域边界,根据支流及流域指标提取河流纵剖面、流域的Strahler曲线,计算其面积高度积分值(Hypsometric Integral,HI)与凹度值,通过函数拟合河流纵剖面形态特征,定量分析延河流域的地貌发育阶段。结合18条河流所处流域的Strahler曲线、河流纵剖面形态特征、HI值及凹度值分析发现:延河流域整体处于地貌发育的壮年期。因岩性和地貌的差异,上、中、下游的发育阶段不尽相同,壮年期偏老的发育状态分布在上游,中下游处于壮年期偏幼阶段。通过拟合凹度值与HI值,发现二者具有一定相关性。用函数拟合河流纵剖面形态特征,验证了延河流域处于发育的壮年期以及上、中、下游的发育阶段不同这一结论。

In this research,Yanhe river basin was selected as the research object. Based on the ArcGIS10. 1 and ASTER GDEM data,the main tributaries of the Yanhe river basin and their watersheds were extracted. According to the tributaries and basin index,the Strahler curves of the river longitudinal profiles and the river basin were extracted,the hypsometric integral value,concavity and fitting function of longitudinal profile were calculated,and the geomorphic development stages of the Yanhe river basin were quantitatively analyzed. Combined with Strahler curve,river longitudinal profile and HI value analysis of 18 river basins,it was found that the Yanhe river basin is in the mature stage. Due to the differences in lithology and geomorphology,the development stages of the upstream,midstream and downstream are different. The upstream is in the older middle age,midstream and downstream are in the younger middle age. It was found that the two have a certain correlation according to the fitting the concavity and HI value.