Ningbo Population Growth And Urban Expansion Evolution Since 1980’s

Since the reform and opening up,China has gradually entered the stage of accelerating urbanization.Some scholars point out that the cities in china have changed in recent decades much more than the western countries in the past century.The typical characteristics of urban development in China are rapid urban expansion and large number of people moving from the village to the cities,especially in the developed areas.The population growth is an important driving factor for land expansion and land expansion will promote the village people into the city.Most of China’s cities basically have been in a low-level and compact state which only meets the basic needs of production and living due to the planned economy.With the deepening reform of economic system the central and local governments attach great importance to urban development,urban space has expanded rapidly since the 1990 s.In most cities,construction land increase have exceeded the population growth in the late1990 s,especially in the eastern developed regions.In this paper,the respectively characteristics of population growth and land use expansion of Ningbo are analyzed,the coordination and coupling relationship in quantity and space between them have been explored in Ningbo from 1982 to 2015 according to remote sensing image data,census data,all kinds of statistical yearbook data and data of overall planning.(1)The evolution of urban land expansionThe related indicators including the compactness,shape index and fractal dimension were introduced to research the features of the external contour of the city according to fractal theory and urban morphological analysis.The relationship between the compact degree and the fractal dimension and the reason of these relationships in different areas were furtherly discussed,which provides a new angle of view for the urban contour form research.Meanwhile,the cold and hot spots pattern and evolution characteristics of urban land expansion have been explored according to the spatial autocorrelation theory and method,which can be combined with the spatial distribution of population growth as an important research basis to make future spatial planning precisely.Simulating to the growth behavior of urban space in multiple periods by SLEUTH model deeply depicts the expansion characteristics of Ningbo and the main growth modes in different periods.It is showed that urban sprawl in Ningbo is increasingly strong with low compact degree and the integration of land expansion decreases,but there is certain differences in each group.At the same time,the hot zone extend from compact spheres mode to the south along the river and sea with significant increasing number of hot zone,the spatial distribution of which is fragmentation,each group adhesion obviously.In general,the overall urban form has been controlled obviously by the natural geographical environment and urban planning control.(2)The evolution of population growthThe census data of four stages are used to analyze the spatial distribution evolution of population growth from population gravity center,population density and spatial autocorrelation characteristics of population density in Ningbo since 1982.Studies showed that Ningbo population had turned to relative diffusion growth since 2000,which is agglomeration in Sangjinagkou in 1982-1990.With the increase of population growth scope population growth tends to balance,but these increase are not evenly.Population growth in Sanjiangkou,Beilun,Zhenhai has differentiated in space.Population density increase are mainly distributed along urban ring roads with a strong autocorrelation of spatial distribution.The spatial distribution of population density is greatly affected by policies,traffic location and industrial layout.Population distribution in Ningbo is still a single-center mode.(3)The spatial and temporal evolution of population growth and land expansionTCPI has been constructed based on the population growth and land expansion coefficient(CPI),the meaning of TCPI and CPI have been analyzed.The coordinate relation and spatial pattern between the population growth and land expansion have been explored from two levels by CPI and TCPI.Meanwhile,the discussion on spatial coupling characteristics and driving force through the gravity model explored the urban development control strategy.It makes the research on population-land relationship rich from macroscopical to microcosmic,from the quantitativity in number to space pattern.Research shows that the coordination degree and spatial coupling degree of populationland evolution in Ningbo have obvious spatial heterogeneity and imbalance.Coordinate degree in Zhenhai and Beilun is lower than the Sanjiang,space coupling relationship of population growth and land expansion gradually weakened and shocked in recent years.Policy,economic development,industrial structure and change of traffic location are the main factors that affect spatial coupling of urban population growth and land expansion.