元谋干热河谷区面积高程积分分析

Hypsometric Integral Analysis of Yuanmou Dry-hot Valley

为识别元谋干热河谷区流域地貌发育阶段,作者以元谋干热河谷区90m空间分辨率的DEM为数据源,利用Arc GIS 10.0水文分析模块提取研究区沟谷系统及其汇水区,以15 000m^2为阈值,计算各区域面积高程积分值。结果表明:元谋干热河谷地貌发育阶段总体上处于壮年期,老年期次之,幼年期最少;幼年期阶段主要分布于1级沟谷区,少数位于2级;壮年期阶段多分布于1—4级沟谷区,即河流的支沟;老年期阶段多分布于5—6级沟谷区,少数分布于4级沟谷区,主要位于中部的元谋断陷盆地,河流的下游及主沟。河流上游的面积高程积分值大于下游,支沟的面积高程积分值大于主沟,面积高程积分值总体上呈现盆地>丘陵>山地。这种空间格局是构造、地貌、岩性等因素耦合作用的结果。本研究不仅有助于认识元谋干热河谷区流域发育特征,也能为水土流失防治及生态修复提供科学指导。

In order to identify the stage of geomorphological evolution of Yuanmou Dry-hot Valley,this paper based on DEM of 90 meters spatial resolution of Yuanmou Dry-hot Valley for the data source,and uses hydrological analysis module in Arc GIS 10. 0 software to extract gully system and its catchment area with 15 000 square meters as the threshold to calculate the Hypsometric Integral in every area. The results show that： The stage of geomorphological evolution of Yuanmou Dry-hot Valley is mostly in the evaluation process of the mature stage,less in the old stage,and the least is in the infant stage; the infant stage is mainly distributed in gully area of level 1,with a few located in level 2; the mature stage is mainly distributed in gully area of level 1 to 4,or in tributary of the river; the old stage is mainly distributed in gully area of level 5 to 6,with a few distributed in gully area of level 4,and mainly is located in Yuanmou faulted basin,which is the downstream or the main stream of the river. Hypsometric Integral value in the upstream of the river is greater than that in the downstream,and Hypsometric Integral value in the tributary of the river is greater than that in the main stream. Generally,Hypsometric Integral value in basin is greater than that in hills,and that in hills is greater than that in mountainous regions. This spatial pattern is the result of the influence on tectonic,geomorphology,and lithology and so on. The study not only can identify the characteristics of the stage of geomorphological evolution of Yuanmou Dry-hot Valley,but is able to provide scientific guidance for soil and water conservation and ecological restoration.