北京上海近20a城市化过程中土地利用变化异同点探析

Similarities and differences of Beijing and Shanghai's land use changes induced by urbanization

城市化进程下土地利用格局变化以及驱动力分析是当前国内学者研究的热点。本文利用C5决策树分类方法分别提取北京、上海1990s以来的三期遥感影像分类图,揭示两市城市用地格局变化的空间规律及其异同点。结果表明:过去的20 a来北京地区以北京市辖区为中心呈现低密度式蔓延扩张;上海城市用地呈"单中心、多卫星城"同时扩张,并且东部沿江地区发展速度较快。将研究区按扩张程度分为:高度扩张区、中度扩张区、低度扩张区。从空间上看,上海城市用地扩张比北京明显,在扩张的过程中占用了大量耕地,上海地区尤为明显。同时,人口增长、产业结构调整等是城市化进程中土地利用变化的主要驱动力因子,需要将来更多的相关研究。

It is important to study land use change driven by urbanization.In this paper,we analyzed TM images since 1990 to reveal the spatial difference of land use changes in Beijing and Shanghai.The results showed that urban area sprawled out from central area with a low density in Beijing,while multi-satellite towns simultaneously developed together with city central area in Shanghai,particularly the eastern part along the river.If we classify the urban expansion into high sprawl,medium sprawl,and low sprawl,the high sprawl area is larger in Shanghai than that in Beijing.During urbanization,a lot of cropland is scarified to provide construction land.Population growth and economic structural changes are the major driving factors of land use changes in urbanization,which need further studies.