Spatial Structure Evolution of Urban Agglomerations and Its Driving Factors in Mainland China: From the Monocentric to the Polycentric Dimension

Urban agglomerations (UAs) have become the urbanized growth poles, especially against the background of increasing population flow to cities. The spatial structure of UAs has been deemed the essential factor affecting regional function and sustainable development. Although there have been many meaningful studies on spatial structure changes in China, a systematically comparative work of UAs is still absent. Under this context, this paper examines the changing process of spatial structure in 20 Chinese UAs from monocentric to polycentric during the years 1992-2012 by using the night-time light dataan alternative to census dataand explores the major driving forces underlying the evolution. Our empirical results suggest that there is an obvious polycentric tendency of UAs, the spatial distribution pattern of which is not apparent. Panel regression models reveal that the economic level, the population size, the foreign direct investment (FDI), the human capital, and the transport infrastructure play significant positive roles in shaping the polycentric changing process, while the growth of the government expenditure does the opposite. Moreover, transport infrastructure and FDI are positively associated with polycentric spatial structure in mature UAs; on the contrary, they are negatively associated with it in the emerging UAs. Our study results have important policy implications for rapid Chinese urbanizationthe policy whereby China's future urbanization development model is to limit the agglomeration of large cities while focusing on developing small and medium-sized cities may be more efficient in mature UAs.