Study On The Change Of Urban Land And Its Relationship With Economic Development In China

Since the reform and opening up in 1978,China's economy has maintained rapid growth for 40 years.With economic development,especially since the beginning of the new century,China's urbanization process is advancing at an unprecedented speed.Urbanization is mainly manifested in the agglomeration of population and nonagricultural industries in cities,and urban land is the place where the economic activities generated by the agglomeration are carried out.The growth of urban population and GDP indirectly leads to the spatial sprawl of urban built-up areas,that is,urban expansion.Urban expansion is a double-edged sword with both disadvantages and advantages.Therefore,taking China's urban land use as the research object,exploring the change of urban land use and its relationship with economic development is of great significance to the formulation of macro-urban planning policies at the national level and promoting the rational and orderly growth of urban land use.Most of the studies on the spatiotemporal dynamics of urban land use take urban land as the single research object.Among the existing studies that integrate urban land,GDP and population,the quantitative evolution is the main focus,and there is a lack of research on spatial evolution.When describing the pattern of urban expansion,there is less autocorrelation between urban land in different regions.In the analysis of influencing factors of urban land or construction land,the heterogeneity of independent variables is not fully considered.To solve the above problems,the vector urban land extracted from the 1:100000 land use database of Chinese Academy of Sciences and the social and economic data in the statistical yearbook are used as the data sources,China's northeast,eastern,central and western regions(four regions)as a division,and the following four aspects are studied.(1)An index is proposed to define the difference of main trend direction of spatial distribution of two types of geographical objects,and the spatial difference index is introduced.This paper constructs a comprehensive index of urban expansion rate,which uses quartile method to grade the urban expansion rate,which is an improvement over the existing achievements.The results show that the main trend difference(UG)between urban land and GDP of secondary and tertiary industries(GDP?ST)in four years(2000,2005,2010,2015)is the largest in western China,and the smallest in northeast China.In terms of the main trend difference(UP)between urban land and population ellipse,it was the smallest in the eastern region in the four years,the largest in the western region in 2000 and 2005,and the largest in the central region in 2010 and2015.The spatial difference of urban land use and population distribution in Northeast China,Central China and West China is monotonically decreasing,and the distribution tends to be consistent.In the same year,compared with the GDP?ST,the spatial distribution of population was closer to the spatial distribution of urban land.From 2000 to 2015,Type A,with both high annual average expansion area and annual average expansion rate,was the most important expansion type,and expansion type A was mainly distributed in economically developed coastal areas.(2)Spatial econometrics model and multi-scale geographically weighted regression model(MGWR)were used to analyze the change of influencing factors and spatial heterogeneity of urban land scale.In 2000,2005,2010 and 2015,at the national scale,GDP?ST,population and urbanization rate all significantly promoted the urban land scale.Comparing the three factors,population played the largest role,followed by GDP?ST,and urbanization rate played the least role.From the comparison of the four regions,among the influencing factors,the positive promoting effect of population on urban land growth is the most obvious.GDP?ST has no significant influence on the urban land scale in Northeast China,while it has a positive and significant influence in the eastern China in four years,indicating that the economic development in Northeast China is less dependent on the new urban land in 2000-2015.In terms of the heterogeneity of the influences of various variables on urban land,the areas with high values of GDP?ST regression coefficient are mainly located in Xinjiang and the Yangtze River Delta,indicating that there is an obvious demand for land in the process of western development.Due to the implementation of the macro policy of Northeast China revitalization,GDP?ST had a great influence on urban land in Northeast China in 2005,and the economic development consumed a lot of land in this period.The areas with high population regression coefficients are mainly distributed in Northeast China,which shows that population plays a decisive role in urban land demand in Northeast China.(3)Based on Cobb-Douglas production function and MGWR,the spatial and temporal characteristics of the influencing factors of economic development were explored.On the national scale,urban land significantly promoted economic growth,and the effect was the greatest in 2010.In the period of financial crisis,urban land supply effectively promoted economic growth.With the development of economy,the promoting effect of science and technology input on economic growth becomes obvious.On the four regional scales,urban land in eastern China has obvious positive promoting effect on economic development during the study period.Investment has always been the main force to promote regional economic development.In terms of the heterogeneity of promoting effect of urban land on economic growth,urban land supply in the Yangtze River Delta,the Pearl River Delta and the southeast coastal areas with relatively developed economy can promote economic growth.(4)Based on spatial autocorrelation,this paper explores the characteristics of urban expansion based on county-level data,and analyzes the spatial spillover effects of influencing factors by using spatial effect decomposition.From 2000 to 2015,in the Beijing-Tianjin-Hebei Collaborative Development Area(BTH),the types with the largest annual expansion area and the largest contribution to urban land expansion were all municipalities directly under the central government.The speed of urban land expansion in Beijing and Tianjin has been significantly higher than that in Hebei,and the characteristics of urban land expansion polarization are prominent.The annual average expansion area high concentration pattern changed from "seesaw" pattern to "dumbbell" pattern.There is an endogenous interaction effect of urban land,and the local urban land is significantly affected by the neighboring districts/counties.A 1%increase in the size of urban land in the neighboring districts/counties will lead to an increase of more than 0.245% in the size of local urban land.In terms of the size of spatial spillover effect,at the county level of BTH,the spatial spillover effect of the average wage of employees on the job is the most prominent among the selected variables.