东北典型黑土区40年来沟蚀空间格局变化及地形分异规律

以SPOT5和Corona影像为基础数据源,获取了东北典型黑土区1965年和2005年的侵蚀沟分布数据,生成了侵蚀沟密度空间分布图;基于1∶5万地形图,插值求取DEM,提取了地形因子;最后,在GIS空间分析模块支持下,分析典型黑土区40年来沟蚀空间格局变化及其地形分异规律.结果表明,经过40年的开发,研究区侵蚀沟密度剧增,且各等级侵蚀沟密度都出现向更高一级发展的趋势,呈现出以北西南东向为轴心,从沟蚀剧烈增加区到微度增加区变化特征;沟蚀在垂直方向上具有层状分布规律,在海拔250～275 m高度出现密度最大值,说明岗坡地带是黑土区沟蚀易发区;坡度分异表明黑土区侵蚀沟出现向高坡度发展趋势;各坡向上侵蚀沟密度和动态发展状况表明,在东北典型黑土区坡向不是影响侵蚀沟发育的首要因子.

Spatial Pattern Change and Topographic Differentia of Gully Erosion in the Type Black Soil Area of Northeast China during the Past 40 Years

Choosing type black soil area of Northeast China which locates in the Wuyuer River and Nemoer River basin as study area,taking SPOT5 and Corona imagery as data source,gully distribution data in 1965 and 2005 were got.Then the gully density was taken as index,and the spatial maps of gully density in 1965 and 2005 were got.At the same time,the 1∶50 000 relief maps were taken as data source,DEM was obtained and the geomorphic factors were extracted.Based on the above data,on the support of GIS spatial analysis function,the characteristics of gully spatial dynamics and change characteristic in 40 years were analyzed.It showed that gully density had obviously increased during the past 40 years.Gully density in each class had the trend to increase to the higher class.The dynamic of gully erosion take North-West to South-East as axial direction and corresponding decrease by the cores to sides.In the vertical direction,gully erosion distribution appeared the layered law,and the maximum of gully density was in the elevation of 250~275 m.It indicated that the hummock-slope was the most possible area to occur gully erosion.According to the slope difference,it showed that gully erosion appeared the trend to come into being on the higher slope.In 1965,the erosion in the area that slope is more than 5° was much lower,but in 2005 it had much serious.The aspect analysis indicated that aspect was not the key factor to cause the gully erosion in black soil area of Northeast China.