Analysis Of The Characteristics And Influencing Factors Of The Spatial And Temporal Changes Of The Shrinking Cities In The Yangtze River Economic Belt

As one of the "three strategies" in China,the Yangtze River economic belt is very important for urban development.In recent years,with the development of regional economy,some cities also have the problem of population loss and economic development deceleration.Studying the problem of urban contraction in the economic zone of the Yangtze River can not only identify the temporal and spatial characteristics of urban development,but also have great significance for the rational construction of the cities in the economic zone of the Yangtze River and promote the sustainable development of the cities.Taking regional economics and urban geography as the subject basis,based on the theory of urban development stage,urban spatial structure theory and population transformation theory,this paper takes110 prefecture-level cities in the Yangtze River Economic Belt as the research unit,selects the data of population density,DMSP/OLS and NPP/VIIRS night lighting from 2007 to 2016 to identify the urban contraction in the Yangtze Economic Belt.The main conclusions are as follows:(1)An analysis of urban contraction based on urban population density found that the contraction in 2007-2016 was the mainstream of urban development in the Yangtze economic zone.The first stage(2007-2011)contraction cities are mainly distributed in the northeast and south-central parts of the Yangtze economic belt and the western marginal areas,and the second stage(2012-2016)contraction cities are mainly distributed in the northern,central and southern areas of the Yangtze economic belt,showing the distribution characteristics ofconcentrated connected pieces.(2)The analysis of urban contraction condition based on city night lighting found that the contraction cities of the Yangtze River economic belt in 2007-2016 mainly appeared in the first stage,and the cities with contraction mainly distributed the northern,central and western regions of the Yangtze economic belt,showing the characteristics of mass distribution.(3)Analysis of urban urban contraction situation based on the comprehensive urban growth rate: from the time point of view,the urban development trend of the Yangtze River economic belt in the decade 2007-2016 is mainly stage contraction,accounting for 24.55% of the total research subjects.From the spatial point of view,the stage contraction city is mainly distributed in the middle of the Yangtze economic belt and the edge city of the economic belt,showing the characteristics of the belt distribution;the continuous contraction city is mainly distributed in the middle of the Yangtze economic belt,and is located at the boundary of each province.(4)Among the three regions of the Yangtze economic belt,middle and lower reaches,the middle reaches have the most contraction cities,the upper reaches are the second,and the lower reaches are the least.From the distribution point of view,the contraction cities in the upper reaches of the Yangtze River economic belt are mainly marginal cities,the contraction cities in the middle reaches spread from the middle to the surrounding areas in a banded way,and the contraction cities in the lower reaches are concentrated in the southern region.(5)The development of cities in the Yangtze economic belt is not only influenced by three factors: regional economic development,regional industrial structure and regional policy support,but also has a great relationship with transportation infrastructure and population age structure.