2000-2018年“一带一路”之中亚5国首都城市扩张的遥感监测

Expansion of megacities in five central Asian countries along“One Belt and One Road”routes(2000—2018)

基于2000、2010和2018年的Landsat TM/ETM+/OLI遥感影像数据,借助GIS技术支持,利用归一化差异不透水面指数(NDII)法提取中亚5国首都大城市的地表不透水面,计算并研究分析城市的扩张强度、扩张速率以及城市空间紧凑性.研究结果表明:1)扩张强度最大的城市是努尔苏丹,为8.75%,最小的是比什凯克,为1.02%;努尔苏丹、塔什干和阿什哈巴德这3个首都城市为减速型扩张类型,比什凯克和杜尚别城市为加速型扩张类型.2)从空间扩张来看,努尔苏丹呈现紧凑型扩张,比什凯克、塔什干和杜尚别城市空间呈现先松散后紧凑的扩张特征,阿什哈巴德城市空间发展呈现先紧凑后维持稳定的特征.3)城市重心轨迹演变分析表明,努尔苏丹、比什凯克和杜尚别18 a间城市重心逐渐向西南方向移动,塔什干和阿什哈巴德城市重心逐渐向东南方向移动.4)从城市扩张与人口和经济因素特征分析表明,人口扩张和经济发展与城市扩张呈现一定的相关性.本研究为建设"一带一路"提供了科学依据,并对中亚5国的城市化发展建设具有一定理论和现实意义.

The five central Asian countries are important locations in the"One Belt and One Road"development strategy proposed by China in 2013.Examination of urban expansion in these five central Asian countries is helpful to promote cooperation and development between countries of the"One Belt and One Road".Normalized difference impervious index(NDII)was employed to extract from three long-time series of Landsat TM/ETM+/OLI imagery(acquired in the 2000,2010,2018)impervious surfaces for the five central Asian countries.Urban expansion intensity,speed and compactness were analyzed.Urban expansion over the past 18 years at 8.75%was the largest in Astana,at 1.02%was the slowest in Bishkek.Urban expansion at Nursultan,Toshkent and Ashgabat decelerated,but at Bishkek and Dushanbe accelerated.For overall space,Nursultan demonstrated a very compact expansion,but at Bishkek,Toshkent and Dushanbe,urban space showed initial expansion,followed by compaction.Ashgabat urban space development was characterized by compactness followed by stability.The gravity of capital from 2000 to 2018 in Nursultan,Bishkek and Dushanbe gradually moved southwest,in Toshkent and Ashgabat gradually moved southeast.Population and economic development was found to have different effect on urban expansion.This study has theoretical and practical significance for urbanization in the five central Asian countries of the"One Belt and One Road"strategy..