Research On Spatial Pattern Of Population Mobility Network In The Yangtze River Delta

As economic globalization and regional integration continue to deepen,the rapid advancement of transportation technology has laid the foundation for normalized and complex intercity travel for residents,thereby promoting the redistribution of economic,social and other elements.Population mobility between cities has also promoted the exchange of material and cultural resources between regions,accelerating the exchange of multiple elements between cities.However,the sudden outbreak of COVID-19 has had a huge impact on intercity travel.Scientifically evaluating the impact of the epidemic on intercity travel is of great significance for scientifically predicting the spread of the pandemic,evaluating urban resilience,and improving travel safety.In this thesis,based on the Amap migration location service big data,the period from 2019 to the first half of 2021 was selected as the time interval,with working days,weekends,return home period,and return to work period as research periods.372 cities in China were selected as research objects,using the Python language to construct intercity population flow networks and utilizing network analysis and GIS spatial analysis methods to analyze the population flow patterns and network structure characteristics of intercity population flow in China at the city,Yangtze River Delta urban cluster,and national levels,and exploring relevant influences on the development of intercity population flow networks.The main conclusions are as follows:(1)During the development of the COVID-19 pandemic,the scale of intra-provincial mobility in the Yangtze River Delta urban cluster has increased,and the flow of population is mainly concentrated within the cluster.Cities such as Nanjing,Hefei,and Suzhou mainly bear the transit pressure of population inflow and outflow.In terms of the spatial distribution pattern of the population,it generally shows a tendency towards proximity of population flow,accompanied by a trend of north-south expansion.(2)The population flow network in the Yangtze River Delta urban cluster is well-developed,and the spatial pattern is generally characterized by a "Z"-shaped network structure with main nodes in cities such as Nanjing,Shanghai,and Ningbo.The main form of this network is a multi-core intercity population flow network,including cities such as Nanjing,Suzhou,Hangzhou,and Shanghai,which has been relatively unaffected by the COVID-19 pandemic.(3)The Yangtze River Delta urban cluster showed a decreasing trend in terms of its ranking in the intercity population flow network during most periods before and after the outbreak of COVID-19.After the outbreak,the flow pressure of migrant workers in China decreased,and the pandemic had a greater impact on cities that rely on the tertiary industry as their main pillar.(4)The floating population in China shows a distribution pattern of "densely populated in the east and sparsely populated in the west" in terms of space.The system of gathering and distributing floating population has hierarchical differentiation characteristics,and the centrality and flattening trend coexist in the urban network.(5)The government’s macroeconomic regulation has a significant practical impact on population mobility in terms of the economy.After the outbreak of the pandemic,the proportion of student mobility in population migration has been increasing in the short term.Hospitals,due to their reception of patients with COVID-19 and the highly contagious nature of the disease,have led people to avoid areas with abundant medical resources to protect their own safety.