基于GIS和RS的延河流域植被覆盖度与地形因子的相关性研究

以延河流域为研究区,综合运用GIS和RS技术,基于Landsat TM影像,运用改进的像元二分模型估算了延河流域2000年和2010年的植被覆盖度,结合DEM数据提取的高程,坡度、坡向地形数据,分析了植被覆盖度与地形因子的相关性,以期为延河流域植被恢复和生态建设提供依据。结果表明:(1)延河流域植被覆盖度从2000年的29.18%增加到2010年的52.42%,呈上升趋势。(2)2000年植被覆盖度随高程的增加呈减小的趋势,2010年植被覆盖度随高程的增加呈先增加后减少的趋势。2000年和2010年植被覆盖度随坡度的升高,大致呈现先升高后降低的趋势,在30°~35°范围内最高。2000年和2010年植被覆盖度总体表现为阴坡(北、东北)半阳坡(东南、西)=半阴坡(东、西北)阳坡(南、西南)平地,其中阴坡的植被覆盖度最高,平地的植被覆盖度最低。(3)在高程1 000~1 500m,坡度在25°~45°范围内,植被覆盖度增加的值最大。

Correlation of Vegetation Coverage and Topographic Factors in Yanhe River Basin Based on GIS and RS

Vegetation coverage of Yanhe River Basin from 2000 to 2010 was calculated from Landsat TM image using mixed pixel decomposition model based on GIS and RS.In order to provide basis for vegetation restoration and ecological construction of Yanhe River Basin,the correlation of vegetation coverage and topographic factors was analyzed combing elevation,slope and slope aspect extracted from DEM.The result showed that vegetation coverage of Yanhe River Basin increased from 29.18％ in 2000 to 52.42％ in 2010;in 2000,vegetation coverage of Yanhe River Basin decreased with the elevation increased;in 2010,vegetation coverage of Yanhe Rriver Basin increased first and then decreased as the elevation increased;vegetation coverage of Yanhe River Basin increased first and then decreased as the slope increased,and was the highest in the lands with gradients of 30°～35°;vegetation coverage in 2000 and 2010 decreased in the sequence:shady slope (north,northeast)＞half sunny slope(southeast,west)=half shady slope(east,northwest)＞ sunny slope(south,southwest)＞flat,the highest vegetation coverage was found in shady slope and the lowest vegetation coverage was found in flat land.The value of vegetation coverage increase was the biggest at 1 000～1 500 m elevation and on the slope with gradients of 25°～45°.