基于QuickBird影像估算晋西黄土区切沟发育速率

切沟的发育不仅破坏土地资源,也是河流泥沙的主要来源之一。为了研究高分辨率遥感影像监测黄土区切沟发育速率的有效性,该文选择晋西黄土区4个小流域,使用GIS技术和2003、2010年同时相QuickBird全色和多光谱影像提取沟谷区面积、周长和支沟沟头前进距离,估算切沟发育速率,并从植被覆盖度、土地利用类型等方面分析了4个小流域切沟发育速率差异的原因。结果显示:2003-2010年,4个小流域沟谷区面积、周长增加比例分别在0.25%～0.48%和1.56%～2.61%;切沟发育主要发生在小流域两侧支沟沟头,支沟沟头大约以0.36～0.44m/a的速率前进;林草地覆盖率越高,小流域切沟发育速率越慢;小流域内沟间地覆盖度大于60%的植被对切沟发育遏制作用明显。研究表明高分辨率遥感能够比较快速、准确地确定切沟发育速率,可为中小流域切沟发育监测提供参考。

Estimating gully development rates in Hilly Loess Region of Western Shanxi province based on QuickBird images

Gully erosion is a significant source of damaging land resources and river sediment. In order to explore the effectiveness of high-resolution remote sensing images in monitoring the development of gully, four small watersheds on the eastern hilly loess plateau were selected to compare changes of the area and circumference of the gully region and the headcut development rate of gully from 2003 to 2010, based on high-resolution remote sensing data (QuickBird images) and GIS. Factors controlling gully development were analyzed including vegetation cover and land-use. The results showed that the increasing rate of area within the gully region ranged from 0.25% to 0.48% in four small watersheds, and the change of circumference was between 1.56% and 2.61% .Gully expanded mainly on side branches with the rate of 0.36-0.44 m/a. Vegetation coverage larger than 60% on the drainage area could evidently inhibit the development of a gully. The change of gully area, circumferences and gully headcut development rates were all smaller in watersheds with more forest coverage. This study suggested that high resolution remote sensing can be used to derive gully headcut development rate quickly and accurately at middle spatial and time scales.