COVID-19疫情前后长三角城市群人口流动结构变化研究

Research on the Change of Population Flow Structure in the Yangtze River Delta Urban Agglomeration Before and After the Outbreak of COVID-19

基于互联网平台提供的2019年、2020年、2021年3月份的人口流动数据,依次代表疫情前、疫情中和疫情稳定后3个节点,运用空间分析和社会网络分析,测度长三角城市群26个城市间的人口流动网络结构时空演化特征,讨论疫情对城市群人口流动的影响。结果发现:长三角城市群整体人口流动强度正逐步向更高一级上升,但疫情的出现暂缓了这种趋势;各省之间人口流动网络密度差异明显,整体上呈现江苏>浙江>总体≈安徽的层次格局,疫情发生后各省之间网络密度变化差异十分显著,其中浙江网络密度上升,江苏和安徽下降;疫情使得城市群人口流动对中间节点的依赖程度显著下降,人口流动模式由通过少数中间节点对外联系,向通过多节点网状模式对外联系转变;疫情发生后,长三角城市群内部集群现象更加明显,且子群内城市构成稳定。

The population flow data in March 2019,2020 and 2021 provided by the Internet platform respectively represents the three time slots before the outbreak of the COVID-19,during the peak of COVID-19 and during the stabilized COVID-19.Using spatial analysis and social network analysis,we measured the spatial and temporal evolution characteristics of the population flow network structure among the 26 cities in the Yangtze River Delta urban agglomeration,and discussed the impact of the COVID-19 on the population flow of the urban agglomeration.The results showed that:the overall population flow intensity of the Yangtze River Delta urban agglomeration is gradually rising to a higher level,but the COVID-19 has suspended this trend.There are obvious differences in the network density of population flow between provinces,showing a hierarchical pattern of“Jiangsu>Zhejiang>overall≈Anhui”.The changes in network density between provinces after the outbreak are also very significant,with the network density increasing in Zhejiang and decreasing in Jiangsu and Anhui.The COVID-19 has significantly reduced the dependence of population flow on intermediate nodes in urban agglomerations,and the population flow pattern has changed from external contact through a few intermediate nodes to external contact through a multi-node mesh model.After the outbreak of the COVID-19,the cluster phenomenon within the Yangtze River Delta urban agglomeration became more obvious,and the composition of cities in the sub-cluster was stable.