中心城市人口集聚对外围城市人口增长的影响--基于多尺度城市体系视角探析

The Impact of Population Agglomeration of Central Cities on Population Growth of Peripheral Cities:Analysis from the Perspective of Multi-Scale Urban System

在城市体系视角下,城市人口规模呈现典型的“中心-外围”空间结构特征。中心城市人口集聚对外围城市人口增长既存在虹吸效应,也存在溢出效应,其具体结果取决于集聚力和扩散力的动态平衡,因而有必要基于多尺度城市体系视角进行考察,探索城市人口有序增长和城市体系合理优化的可行路径,为考察城市体系下城市间人口增长的空间效应提供有益参考,实现“大中小城市协调发展”的城市化战略。本研究利用中国1990—2020年城市面板数据,基于全国、省域和城市群层面的多尺度城市体系构建包含空间效应的计量模型,实证探讨中心城市人口集聚对外围城市人口增长的影响效应及地理范围。研究表明:第一,不同层面中心城市人口集聚对外围城市人口增长均存在显著的虹吸效应,经过更换因变量、更换估计方法和补充遗漏变量等一系列稳健性检验后结果仍然显著。第二,在全国和省域城市体系下,国家和省域中心城市人口集聚对东部县级市人口增长具有溢出效应,而对其他类型城市人口增长具有虹吸效应,且对内陆地级市的虹吸效应明显高于东部地级市;此外,国家中心城市人口集聚对高等级城市的虹吸效应最大。第三,在城市群城市体系下,长三角和珠三角城市群的中心城市人口集聚对外围城市人口增长具有显著的溢出效应,而京津冀、长江中游和成渝城市群存在显著的虹吸效应。第四,外围城市人口增长还会受到地理距离影响,加入地理距离后的模型回归结果显示中心城市人口集聚虹吸效应的地理范围主要在250公里范围之内,且呈现随着距离增加而递减的态势。为促进外围城市人口增长,既要科学认识中心城市的虹吸效应,注重发挥中心城市的溢出效应以释放其人口规模集聚红利;也需要外围城市主动融入城市体系,与中心城市建立较强的空间联系,以积极承接中心城市产业人口转移;此外,还需要重视外围城市自身经济、产业和财政等因素对其人口增长的促进作用,并加快构建城市体系内高效快捷的综合交通运输网络体系,最终形成区域城市人口协调发展格局。

Urban population size presents a typical"center-periphery"spatial structure feature from the perspective of urban system.The population agglomeration of central cities has both a siphon effect and a spillover effect on the population growth of peripheral cities.The specific results depend on the dynamic balance of agglomeration and diffusion forces.Therefore,it is necessary to examine it from a multi-scale urban system perspective and propose feasible paths for orderly urban population growth and rational optimization of urban system,which can provide useful references for understanding the spatial effects of population growth between cities under the urban system,and help to achieve the urbanization strategy of"coordinated development of large,medium-sized and small cities".Based on urban panel data in China from 1990 to 2020 and the multi-scale urban systems at the national,provincial and urban agglomeration levels,this paper constructs an econometric model that includes spatial effects to empirically explore the impact of population agglomeration of central cities on population growth of peripheral cities and its geo⁃graphical scope.The results show that:firstly,population agglomeration of central cities in different levels have significant siphon effects on population growth of peripheral cities,and the results are still significant after a series of robustness tests,such as replacing the depended variables,replacing model estimation methods and supplementing missing variables,etc.Secondly,from the perspective of national and provin⁃cial urban systems,population agglomeration of national and provincial central cities has a spillover effect on the population growth of eastern county-level cities,while it has a siphon effect on the population growth of other types of cities.Siphon effect on prefecture level cities in the inland region is significantly higher than that of eastern cities.In addition,population agglomeration in national central cities has the greatest siphon effect on higher-level cities.Thirdly,from the perspective of urban systems in urban agglomerations,population agglomeration of central cities of the Yangtze River Delta and Pearl River Delta urban agglom⁃erations have significant spillover effects on the population growth of peripheral cities,while the Beijing Tianjin-Hebei,Yangtze River middle reaches,and Chengdu-Chongqing urban agglomerations have signifi⁃cant siphon effects.Fourthly,the impact of population agglomeration of central cities on population growth of peripheral cities is also affected by geographical distance.The regression results of the model with added geographical distance show that,the geographical range of siphon effect of population agglomeration in central cities is mainly within a range of 250 kilometers,and it shows a decreasing trend with increasing distance.To promote population growth in peripheral cities,it is necessary to scientifically understand the siphon effect of central cities,and focus on leveraging the spillover effect of central cities to release their population agglomeration dividend.Then,it is also necessary for peripheral cities to actively integrate into the urban system,establish strong spatial connections with the central city,and actively undertake the trans⁃fer of industrial population from the central city.In addition,it is also necessary to attach importance to the promoting effect of economic,industrial,and financial factors of peripheral cities on their population growth,and accelerate the construction of an efficient and fast comprehensive transportation network system within the urban system,ultimately forming a coordinated development pattern of regional urban population.