基于中尺度的滥泥河流域1990-2005年沟道变化研究

Gully Changes of Lanni River Watershed During 1990-2005 Based on RS at Meso-scale

利用3S技术和传统技术研究沟道侵蚀变化已成为国内外研究的热点。研究以1990年和2005年两期Landsat/TM影像及1∶5万地形图为基础分析数据,以宁夏回族自治区西吉县滥泥河流域为研究区,在GIS、RS等分析软件的支持下,基于DEM自动提取两期沟道网络,同时利用DEM提取与沟道相关的因子:坡度、坡向、沟道长度、沟道深度、沟壑密度、纵比降等,并通过两期TM影像提取出沟道宽度。根据研究的需要,选取沟道长度、沟道宽度、沟壑密度和纵比降作为分析沟道变化的判别指标。最后通过选取的4个判别指标,分析滥泥河流域近20a沟道变化情况。

The use of 3S and traditional techniques has become a hot topic worldwide in studying gully ero- sion changes. In this study, we take Landsat/TM images in 1990 and 2005 and 1 ： 50 000 topographic map as source data, and take Lanni River Watershed in Xiji County in Ningxia Hui Autonomous Region as the study area. The study was supported by GIS, RS and other analysis software, 2 gully networks based on DEM were extracted automatically. In the same time, factors of slope, aspect, gully length, gully depth, ravines density, vertical slope related channel were extracted from DEM, and the gully width was by 2 TM images. According to the research needs, gully length, gully width, gully density and vertical slope were selected as the evaluation indexes to analyze gully changes of Lanni River Watershed during the past 20 years.