中心城市产业结构对腹地城市人口增长及区域城市体系演化的影响

The study of the new economic geography has paid attention to the polarization and balanced development of urban systems. In reality, however, transport accessibility is subject to great uncertainty in explaining the polarization and balance of the urban system. In fact, the polarization or equilibrium of the regional urban system is not only unique in China, but also a general phenomenon in countries with different development outcomes, political systems and degrees of marketization. From the perspective of industrial heterogeneity, this study empirically analyzes the process and mechanism of the industrial structure of regional central cities on the population growth of neighboring cities in China from 1980 to 2020, and examines the influence of industrial structure on the polarization and equilibrium development of the regional urban system. The results show that, firstly, the manufacturing sector strengthens the spillover effect from the core city and promotes the population growth in neighboring cities, while the service sector weakens the spillover effect and hinders the growth in neighboring cities. Secondly, the manufacturing- oriented cities have relatively small city scale, while the service- oriented cities are relatively large. Therefore, the driving effect of manufacturing-oriented central cities on the neighboring cities is larger, which tends to produce a relatively balanced regional city system. Correspondently, the spillover effect of service-oriented central cities on the neighboring cities is smaller, which tends to form a relatively polarized regional city system. Finally, as the share of services in the industrial structure of central cities continues to rise, China's urban system may become more polarized rather than balanced. Certainly, the higher the proportion of manufacturing in the central city, the more balanced the regional urban system is. In fact, the empirical results show that the industrial structure and the spillover effect of the core city have an inverted U-shaped relationship, i.e. a high proportion of manufacturing or services weakens the driving effect of the core city on surrounding cities. The reasons for this vary. The high proportion of manufacturing and the small size of the central city have a limited spillover effect on the neighboring cities and therefore can hardly drive their growth; while the high proportion of service industry and the negative effect of the service industry on the spillover effect lead to the slow development of the neighboring small-and-medium-sized cities. It is worth noting that because of the significant spatial impact of industry on the urban system, the future regional urbanization strategy should be coordinated with the industrial strategy. More importantly, with the gradual liberalization of the household registration system, industry selection can become an effective policy option for macro- control of the regional urban system.