Characteristics And Factors Driving Population Flow In The Pearl River Delta Urban Agglomeration From The Perspective Of Internal And External Networks

The Pearl River Delta(PRD)urban agglomeration is one of the important economic center regions in China.Promoting the integrated development of the PRD urban agglomeration has a prominent driving role and a crucial strategic position in the construction of China’s urban agglomerations and the development planning of the Guangdong Hong Kong Macao Greater Bay Area.Population flow is often accompanied by the flow of economic,information,technology and other factors,reflecting the status and rank of regional cities,which is the intuitive expression and external result of city interconnection.Currently,the study of urban mobility networks based on social network analysis methods has become mainstream.However,the characteristics of internal linkages among PRD urban agglomerations and their linkages with major external cities still need to be elucidated.To this end,this paper takes the Gaode Migration Big Data as the main data source,selects 2019—2021 as the time range,and constructs population mobility networks from the perspective of the internal and external networks of the PRD urban agglomeration,taking nine prefecture—level cities in the PRD urban agglomeration and 31 provincial capitals across China as the research objects respectively.Using tools such as UCINET,Gephi and Arc GIS,the internal and external population mobility networks of the PRD urban agglomeration are explored for different time periods(the whole year,the Spring Festival,the National Day and the daily period)through social network analysis methods and GIS spatial analysis,respectively,to analyze the characteristics of network structure changes.The QAP regression analysis method and simple exponential random graph model are used to study the influencing factors of the formation and changes of population mobility networks.The main findings of this paper are as follows:(1)From 2019 to 2021,the population flow network within the PRD urban agglomeration shows an "N" shaped structure throughout the whole year,the Spring Festival,the National Day and the daily period.The network connection within the city cluster is dominated by the connection between the core cities Guangzhou and Shenzhen and their neighboring cities,with obvious spatial proximity characteristics.The network pattern shows the trend of integration of Guangzhou—Foshan and Shenzhen—Dongguan—Huizhou metropolitan areas.The cities with net population outflow are concentrated in the western and central parts of the PRD urban agglomeration,the cities with net population inflow are mainly concentrated in the southern part of the region,and the cities with more balanced population inflow and outflow are distributed in the eastern part of the region.Throughout the year and during the daily period,the network density within the urban agglomerations is strengthening,the cities are more closely connected with each other,and the urban agglomeration network is developing in a good manner.The network density decreases and then rises during the Spring Festival,decreases continuously during the National Day,and the network structure is looser during the holidays.(2)The characteristics of the 2019—2021 population mobility network between the PRD and provincial capitals are manifested in the Whole Year,the Spring Festival,the National Day and the Daily Period: city hierarchy decreases outward in a circle—like pattern with increasing distance;the PRD urban agglomeration has the highest centrality in the network;and the PRD is located in the largest community and contains the largest number of cities.The number of cities and the intensity of the PRD’s external links are relatively weak during the whole year,the National Day and the daily periods,and the intensity of the PRD’s links with the national capital cities is highest during the Spring Festival.Network density increases during the whole year,rising and then falling during both the National Day and daily periods,and falling and then rising during the Spring Festival.2020 has the weakest intensity of PRD’s external links during the Spring Festival,with the lowest number of cities included in the community.(3)The results of the analysis of the factors influencing the internal network show that geographical distance,education level,and social security level are important factors influencing population mobility within the PRD urban agglomeration.Overall,cities with smaller differences in GDP,geographic distance,education level and healthcare level promote population mobility and cities with larger differences in social security level are more conducive to population mobility during the whole year and daily period of 2019.In 2020—2021,for the whole year and daily period,economic level no longer plays a dominant role,and cities with similar distance and education levels are more attractive for population mobility.Cities with greater differences in the level of social services,health care and social security are more favorable to mobility.The restrictive effect of distance on travel first increases and then decreases,and people pay more attention to the level of urban welfare and medical health.In terms of holidays,the level of urban education and social security are the main factors influencing population mobility.GDP,public service level,medical level and employment rate are gradually becoming important influencing factors for people to travel.(4)The results of the analysis of the factors influencing the external population mobility network show that population mobility is generally bidirectional.Overall,the level of scientific research,social security and employment are significant factors promoting urban population linkages during the whole year and daily period in 2019,and the share of tertiary industry structure and geographical distance are negatively correlated with population mobility.The level of social services is no longer significant during the whole year and daily period in 2020,and the attributes of other factors remain unchanged.In terms of holidays,the level of social security and geographical distance are the main factors influencing inter—provincial population mobility.The level of scientific research,education,medical care and salary level have less influence on people’s interprovincial travel,and people’s demand for urban social security level is increasing.