中国大都市多中心空间演化过程的非均衡动态模拟

构建了一个基于垄断竞争、规模经济、空间成本、消费者多样化偏好以及商品和服务差异化的大都市多中心空间结构模型,并整合基于agent的建模,借助非均衡(out-of-equilibrium)动态模拟,探讨了人口规模和消费需求、区域间和区域内商业产品及服务的替代弹性、固定成本投入、区位和交通条件等因素的"持续"变化对的大都市空间结构演化的影响过程。模拟表明:以商业为代表的经济活动往往集聚在具有区位优势、规模经济和消费能力的大都市传统中心,而交通条件的持续改善、新兴郊区次中心与传统城市中心之间以及城区内部商业产品和服务的不断差异化对大都市的多中心空间结构有重要影响,但影响的程度不同。更重要的是,大都市的人口规模和消费能力对新兴郊区次中心的形成作用显著。

Non-equilibrium dynamic simulation of spatial evolution of the polycentric structure in metropolitan areas of China

Since the 1990s, cities in China have experienced a period of rapid growth in economy. In face of the increasing complexity of the urban sprawl, many big cities are planning to build new towns to avoid over-intensive population and infrastructure construction and to ease the pressure on urban centers. Some findings show that the rapid increase of the share of service industries in the local economy can raise the probability of the emergence of subcenters. This paper builds a mathematic model of spatial structure of metropolitan commerce based on the theory of New Economic Geography in old and new center scenarios. By using agent-based modeling and out-of-equilibrium simulation, the spatial structure of subcenters can be observed dynamically in different scenarios. Dynamic simulations show that: (1) Population growth in metropolitan area is conducive to subcenters which implies the commercial centers emerged in the suburban areas were mostly subjected to population pilot policy. (2) The continuous growth of demand scale and capacity depend on the formation of the polycentric structure in metropolitan areas. The capacity of consumptions has great impact on agglomeration of subcenters. (3) The greater the gap of commercial fixed input between the new and old centers is, the more imbalanced urban space distribution would be presented. It is more likely to form the core-periphery structure. If the fixed cost is reduced continuously in suburban areas, it is beneficial for the formation of subcenters and the core-periphery structure of metropolitan areas could be changed gradually. (4) Transportation is a double-edged sword. Commerce and business tend to gather in the place with location advantages, and continuous improvements in traffic condition between old and new centers in metropolitan areas will accelerate the spatial concentration in the old center. The probability of the emergence of subcenters decreases with the increase of the distance to the city center, which implies the subcenters emerged in the metropolitan areas were mostly close to the central area of the city and the decentralization of population in the metropolitan areas was still limited in spatial scale. (5) Due to love-of-varieties, the specialization and diversity make great contribution to the formation of subcenters in metropolitan areas by continuous innovation and difference-making competition strategy.