Research On The Coordinated Development Of Urban Optimal Scale And Cities Of Different Scales Based On Space Efficiency

After 40 years of market-oriented and globalized economic reforms,China's huge economic vitality has been unprecedentedly released,and the economic geography has also undergone multi-stage reshaping.Similar to the characteristics of the global economic geography,China's economic geography is not flat either.The concrete manifestation is the trend of urbanization and urban agglomeration.At present,China's urban economic scale has accounted for 90%of the total economic volume and total trade volume;the three major urban agglomerations of the Yangtze River Delta,the Pearl River Delta,and the Beijing-Tianj in-Wing have become China's economic growth poles,accounting for 3.5%of the country's land.The area has created 41.2%of the country's GDP.From a worldwide perspective,the economic activities of all countries in the world are clustered together in a few big cities and big cities,and the more economically prosperous countries or regions are,the higher the spatial concentration of the economy is.Economic agglomeration has promoted the specialization and complementarity of production,and formed the knowledge spillover effect and the industrial linkage effect.Regional differences in productivity have prompted labor and capital and other economic factors to flow to big cities.However,the spatial gap caused by economic agglomeration has caused the developing countries with rapid urbanization to generate conservative political tendencies towards urbanization.Giving consideration to efficiency and fairness is the long-term guideline for China's economic and social development.From the perspective of economic geography,the use of efficiency means following the economic laws of the convergence of factors to big cities,thereby maximizing the overall efficiency of the country's space;achieving fairness is to ensure maximum sharing of development results.This requires that Reducing inequalities in terms of per capita income between regions.Since the 1980s,the perception of"restricting the scale of large cities and giving priority to the development of small towns" has occupied the mainstream of urbanization in China.Although it has been constantly questioned and controversial,it has tried to restrict the development of large cities for small and medium-sized towns.The spatially balanced policy of creating space for development has never retired from the official discourse system.The principle of urban development based on the control of the scale of large cities has given birth to a distorted urban scale structure and a flat urban spatial structure,which has resulted in a low spatial economic efficiency.Henderson(2006)pointed out that China's policy of restricting urban development,such as immigration restrictions and national urban planning,has kept Chinese cities too small.Fujita et al.(2004)pointed out that compared to most developing and developed countries,Chinese cities are smaller and more evenly distributed.So,does our country's economy have excessive concentration?Is the economic development of China's big cities and small and medium-sized cities mutually exclusive?In the sense of space,can efficiency and fairness go hand in hand?For this series of issues,this paper discusses the issue of coordinated development between China's optimal city size and cities of different scales under the framework of space efficiency.The core point of this paper is that agglomeration of economic activities to big cities will be conducive to the exertion of space efficiency.At the same time,if there is free flow of labor across regions,the coordinated development of large,medium and small cities will ultimately be achieved.Specifically,the article demonstrates the core ideas from the following aspects.First,taking the spatial structure model as the theoretical foundation,the preference of producers for the intermediate input products reflects the agglomeration strength of urban economy,the optimal urban size as agglomeration economy caused by the diversification of intermediate products and the agglomeration caused by congestion Uneconomical results of the two opposing forces to check and balance each other,thus deducing the inverted U type of net salary-the city scale curve,thus demonstrating the existence of the optimal city size.Through the measurement test,we estimate the optimal scale of different types of cities in China,and draw the conclusion that the economic scale of most cities in China is small.Second,taking the 108 small cities in the Yangtze River Delta as the research samples,adding the factors such as geographical distance,administrative boundary and market potential in the traditional economic growth model to the estimation of the spatial impact of different levels of big cities on the economic growth of small cities And its heterogeneity.It is found that the proximity to big cities helps to promote economic growth in small cities.The direction of spatial interaction is more reflected in the influence of high-level cities on low-level cities.Sub-provincial cities have the most significant growth spillover.Among small cities with the same level,The spatial correlation effect is relatively weak.There is a certain degree of market segmentation among cities,and the existence of administrative boundaries hinders the development of space spillovers.Thirdly,taking the 133 counties and cities in the Yangtze River Delta as samples,this paper constructs an economic growth model that contains the market potential as the key explanatory variable,and reveals the impact of market potential on the regional economic growth gap from the perspective of spatial efficiency.It is demonstrated that the labor mobility is conducive to exerting economies of scale and promoting the convergence of economic growth among cities in large,medium-sized and small cities,that is,achieving a win-win result of space efficiency and balance.The conclusions of the study provide a scientific basis for economic benefits in promoting China's new urbanization strategy.First of all,we must respect the objective laws of urban development.The formulation of urban scale planning must conform to the development laws of agglomeration economies,continue to deepen the implementation of the household registration system reform,and strive to achieve a breakthrough in eliminating institutional barriers to population mobility and high-grade cities,especially large cities..We will continue to deepen the urbanization spatial pattern with urban agglomerations as its main form,and enhance the radiating fimction of central cities so as to give play to the economic development of small cities and achieve the coordinated development of large,medium and small cities.