近40年老哈河流域土地利用变化监测与分析

利用决策树和支持向量机分类方法,基于多期Landsat MSS,TM and ETM+遥感图像和其他辅助数据,对1970s以来近40年半干旱的老哈河流域土地利用变化(land use and land cover change,LUCC)进行动态监测,并利用GIS方法对LUCC进行了定量分析和空间分布制图.结果显示,利用支持向量机分类方法对该地区1976年、1989年、1999年和2007年土地覆盖类型分类可达到较满意的效果；近40年老哈河流域土地利用变化显著,水体和草地减少,城乡用地持续扩张,耕地大幅增加,林地和未利用地大幅度波动、总体减少.LUCC主要发生在林地、草地和耕地之间,表明农、林、牧用地之间转换显著,且在各个时期的空间分布差别较大.从变化强度来看,土地利用的年综合变化率最大值渐趋增大,年均土地动态度在空间分布上差异很大,另外在各研究期赤峰市区周边动态度都很大,反映了赤峰市持续性的城市化进程.

The Detection and Analysis of Land Use Change in the Laoha River Basin During the Past Four Decades

On the basis of the multiple remote sensing images of Landsat MSS,TM and ETM+ and other auxiliary data,two classification approaches of decision tree and support vector machine were applied to land use/cover classifications in the semiarid Laoha river basin over the past 40 years since the 1970s.The land use changes and their spatial distribution were analyzed quantitatively and mapped with GIS techniques.The results show that land use/cover maps in 1976,1989,1999 and 2007 could be generated based on the implementation of support vector machine classification with satisfying results.The analysis shows that land use has changed very obviously in the study area over the last 40 years.The areas of water body and grassland have decreased while rural and urban areas increased persistently.The cultivated land area has increased substantially.Forest land and fallow land have changed in fluctuation with a decrease on the whole.It’s obvious that the most remarkable change has been the interconversion of lands for agriculture(cultivated land),for forestry(forest land),and for animal husbandry(grassland).Moreover,the spatial distribution of the conversion was greatly different in different periods.An analysis of the intensity of land use changes indicates that the highest annual rate of land use change has been increased gradually and the annual intensity has been spatially heterogeneous.Moreover,the suburbs surrounding Chifeng city always have changed intensively during the past decades,suggesting the persistent urbanization of Chifeng city.