Multilevel Analysis Of Driving Mechanism And Simulation Of Urban Agglomeration Expansion Considering Spatially Inter-city Interactions

Rapid development of urbanization in China has brought a powerful impetus to social development,which accelerated the depletion of natural resources and the degradation of the ecological environment,threatening food security and ecological security.To control of urbanization development scientifically,it is necessary to deeply understand the internal mechanism of urban expansion and master the process of urban expansion.With the continuous enhancement of the spatial interaction between cities and regions,China’s urbanization has gradually moved towards the stage of coordinated urban development,and urban agglomerations have become the main form of national new urbanization construction.Considering the above research background,this study explores the multi-level influence mechanism of urban agglomeration spatial expansion by constructing a Hierarchical Linear Model(HLM),and constructs a Cellular Automaton model based on it to analyze typical urban agglomerations in different regions.The main research contents and conclusions are as follows:(1)Construct a HLM and analyze the characteristics of scale differentiation and regional differentiation of the driving mechanism of urban expansion in the main urban agglomeration from 2005 to 2015 at multiple scales.The results show that:(1)On the city scale,population growth,economic growth,industrial structure optimization,and urban location conditions have all accelerated land urbanization.On the contrary,the increase in fiscal deficits and the intensive use of urban land have hindered it.The driving factors present significant regional differences.The main driving force for the expansion in coastal areas comes from the increase in urban population and the rapid development of the tertiary industry.Stimulation of industrial demand,location and strategic position of cities are influencing factors of inland areas.(2)At the scale of the urban agglomeration,the total gravity of the spatial economic connection has a positive effect on the expansion,and the increase of the external function will bring resistance to it.Moreover,the total gravity of the spatial economic connection has a significant role in promoting it in coastal areas,while the outward functional force has a negative effect in the expansion of inland urban agglomerations.(2)Construct a cellular automaton model for urban agglomeration expansion simulation based on multi-level influence mechanism.Simulate and verify the process of urban land expansion in the Pearl River Delta urban agglomeration in coastal area and Chengdu-Chongqing urban agglomeration in inland area,predict and analyze the urban expansion process in 2020 and 2025.The results show that:(1)The CA model constructed in this study has a good simulation effect.The total accuracy,kappa coefficient and Fo M accuracy all verify the accuracy of the model,and the comparison results of simulation accuracy in different scenarios of the two urban agglomerations also confirm this conclusion;(2)Spatially inter-city interactions can promote the expansion of Pearl River Delta agglomerations,and it has a more obvious effect on developed cities.It also has a certain optimization effect on the expansion model of urban agglomerations.Spatially inter-city interactions also reduces the increase in urban land use in Chengdu-Chongqing urban agglomeration,whose two core cities have caused a squeeze on the cities near their center,and has created resistance to the further expansion of these cities.On the contrary,it has little effect on the expansion intensity of remote cities.In summary,this article focuses on spatially inter-city interactions,which is helpful to deeply understand the internal mechanism and evolution process of urban agglomeration space expansion in the new era,and provides a basis for scientifically formulating urban planning and guiding urban construction practices.