共享社会经济情景下“一带一路”沿线国家城市扩张空间格局分析

Urban Spatial Pattern and Expansion Characteristics in Countries along the Belt andRoad under Shared Socioeconomic Pathways

探索“一带一路”沿线国家和地区未来城市空间格局及扩张特征可为优化城市空间、促进生态环境可持续发展以及统筹推进各国城市优先建设领域的互连互通提供数据支撑。该文基于土地与社会经济面板数据,利用最小二乘虚拟变量回归法预测共享社会经济情景(Shared Socioeconomic Pathways,SSPs)下“一带一路”沿线62个国家及地区2020—2060年城市用地增量,利用FLUS(Future Land-Use Simulation)模型模拟城市空间格局,从人口密度与城市扩张关系视角分析SSPs情景下研究区城市空间扩张特征。结果表明:①2020—2060年“一带一路”沿线国家(地区)城市空间呈现明显扩张趋势,SSP1(经济全球化)与SSP5(常规发展)情景下城市空间扩张程度较激烈,SSP3(局部发展)情景下相对较弱。②城市用地空间分布在不同情景下存在明显差异,具体表现为当国家城市化发展较快、国民经济水平较高时,扩张以城市斑块集聚外延为主;当国家城市化与国民经济发展速度放缓,扩张则以城市斑块相对均匀分散为主。③“一带一路”沿线国家(地区)中超过83%的超大城市呈现松散增长的空间扩张模式,54%的中小城市呈高人口密度—紧凑增长的扩张特征,其中,东亚地区多数城市和欧洲西部城市呈低人口密度—松散增长的扩张特征,中亚及东南亚地区的小城市以高人口密度—紧凑增长的扩张特征为主。

Exploring the future urban spatial pattern and expansion characteristics of countries and regions along the Belt and Road can provide data support for optimizing urban spatial development,promoting the sustainable development of ecological environment,and contributing to the interconnection of priority construction areas of cities in various countries.Based on the panel data,the least square regression method of dummy variables was used to forecast urban land growth in 62 countries and regions along the Belt and Road from 2020 to 2060 under the shared socioeconomic pathways(SSPs),and future land-use simulation(FLUS)model was used to simulate the urban spatial pattern of the countries and regions in 2060.From the perspective of the relationship between population density and urban expansion,the spatial expansion characteristics of key cities in the countries and regions along the Belt and Road were analyzed under five scenarios of SSPs.The results are as follows.①From 2020 to 2060,the trend of urban spatial expansion in countries along the Belt and Road is obvious,and the degree of urban spatial expansion is more intense under the scenarios of SSP1 and SSP5,and relatively weak under SSP3.②Under different scenarios of SSPs,there are significant differences in the spatial expansion characteristics of urban land in different countries.Specifically,the faster the urbanization of a country is and the higher the national economic capacity is,the expansion is dominated by the agglomeration and extension of urban patches.When the speed of urbanization and national economic development slows down,the expansion is relatively evenly distributed in urban patches.③More than 83%of megalopolis in the countries show loose urban spatial expansion pattern,54%of small and medium-sized cities show compact urban spatial expansion pattern.Among them,and most cities in East Asia and Western Europe show loose urban spatial expansion pattern with low population density,the small cities in Central Asia and Southeast Asia are mainly characterized by compact urban spatial expansion pattern with high population density.