Land Use Change in the Watershed of the Ningxia-Inner Mongolia Reaches of the Yellow River During 1990-2010
Using Landsat TM and ETM+ satellite images as the basic data source,adopting geographic information system,we monitored land use change in the watershed of the Ningxia-Inner Mongolia reaches of the Yellow River during 1990-2010,then discussed the driving force of land use change by combining with climatic factors,human activities and policy factors,finally,analyzed the effect of vegetation coverage change on runoff and sediment load.Results showed that:(1) During 1990 2010,the area of constructive land and farmland increased by 1 310.04 km2 and 611.15 km2,respectively,however,the area of wetland and grassland decreased by 1 499.51 km2 and 474.93 km2,respectively.(2) The land use change in this basin experienced a process of slow change-obvious change-tremendous change in 1990-2000,2000-2005 and 2005 2010.The speed of land use change was greater in 2000-2010 than that in 1990-2000.(3) The major patterns of land use change were the conversions of grassland and unused land to forest,farmland and grassland to constructive land,as well as unused land and grassland to farmland.(4) The variation of land use change was mainly affected by human activities and policy factors.Population increasing,economy development and environmental protection policy had significant effects on land use change.(5) During 1990 2010,the area of forest land and farmland increased by 543.19 km2 and 611.15 km2respectively,which increased evaporation and irrigation water,thus reduced runoff.Vegetation coverage was increased from 34.7％ in 1990 to 40.8％ in 2010,which made the annual runoff and sediment load decreased significantly.
Yellow Riverwatershed of the Ningxia-Inner Mongolia reachesland use changedriving force
NETL
NSTL
万方数据
