Allometric Growth Of Urban Land And Population And Their Driving Force In Typical Urban Agglomerations

Since the reform and opening up policy,China's urbanization process has made a milestone progress.China is currently in the rapid development of urbanization.The acceleration of the urbanization process promotes that the urban land expands rapidly and the contradiction between man and land becomes more and more prominent.The urbanization process is accompanied by the long-term problem that population urbanization lags behind land urbanization.The imbalance between the two will affect the quality of China's urbanization process and the development of economy and society.In this paper,the Beijing-Tianjin-Hebei urban agglomeration,the Yangtze River Delta urban agglomeration and the Pearl River Delta urban agglomeration are studied.First,this paper studies the spatial and temporal characteristics of land expansion and population growth in three urban agglomerations from 2000 to 2014.This paper analyzes the current situation and the trend of land expansion and population growth in the three major urban agglomerations.It can be seen that the rates of land expansion and population growth of three major urban agglomerations shows the commonality of spatial distribution,in other words,the diffusion effect from the central city to the surrounding.The overall temporal variation trend also shows a certain degree of similarity,with three stages of variation:rapid growth,gradually decline and stabilizing.Secondly,the allometric relationship between land expansion and population growth in the three major urban agglomerations is studied.It is found that the three major urban agglomerations show a serious positive allometric growth.In the 15 years in 2000-2014,the scale factor is from 0.85 to 1.3.The rate of land expansion is greater than of population growth,we should pay more attention to population urbanization in the coordinated development of the three urban agglomerations..Finally,this paper studies the influencing factors of urban land expansion and population growth,and analyzes the expansion of urban built area and the growth of population from four aspects:market force,administrative force,endogenous force and outward force.In this paper,the fixed-effect regression model of panel data is constructed,and the dynamic panel model is fitted and optimized.The driving mechanism is compared and analyzed.The results show that the driving forces of urban land expansion and population growth are shown differently in different urban agglomeration.The endogenous force is more effective than the outward force to promote the effective growth of the urban population,and the administrative force is more effective than the market force to curb the trend that urban land expansion is faster than the population growth.The endogenous force is the ideal motive force to promote the coordinated development of land expansion and population growth.The market force is the basic driving force for the coordinated development of land expansion and population growth.The administrative force is the important auxiliary force to ensure the harmonious development of land expansion and population growth.We should take the advantage of regional characteristics in the development of urban agglomerations,with efforts to enhance the endogenous force in the promotion of population urbanization.Based on the dertermination of market force in the resouces allocation,we should reasonably allocate the resource in the urban agglomeration.At the same time,we should strengthen the coordination effect of administrative power on the relationship between land and population and control the strong negative impact of outward force on the coordination relationship of land and population.According to the results,the three urban agglomerations have the problem that the land expands faster than the population grows.The market force and the administrative force of the Beijing-Tianj in-Hebei urban agglomeration is reflected in the synergistic effect in the development of land and population.It should focus on improving the quality of endogenous force,enhance the attractiveness and placement to the population.The Yangtze River Delta urban agglomeration should try to continue to play the good role of endogeneous force in coordinating the relationship between man and land,and further enhance the effect of administrative force on the promotion of population urbanization.In the process of coordinated development of the Pearl River Delta urban agglomeration,the market force and the administrative power are not the reason why the land expansion is faster than the population growth.It is very important to control the outward force which have a strong negative effect on the coordination relationship of land and population.