“人口流动”视域下中国城市中心性和社群格局分析

Analysis of Urban Centrality and Community Patterns from the Perspective of "Intercity Mobility Flow" in China

城市网络的组织结构与运行机制离不开城市间的关联关系。本文基于2021年10月至2022年9月的百度迁徙大数据,构建了中国366个城市的城际人口流动网络。在节点层面,提出了城际人口流动超越指数衡量城市中心性,探索城市中心性的空间聚类特征;在网络社区层面,分析了中国366个城市的月际城际人口流动特征及社群格局。结果表明:(1)城际人口流动超越指数能够有效表征城际人口流动网络中各城市的中心性;(2)城际人口流动网络中各城市根据其中心性形成“高高”集聚分布和“低低”集聚分布的特征;(3)城际人口流动集聚格局受节假日因素、新型冠状病毒感染等综合影响,在不同月份表现出不同的特征,总体上符合地理学第一定律,并呈现省际分异特征;(4)城市凝聚子群发现结果表明,成渝、大湾区、中原、关中平原、长三角等城市群人口流动格局较为稳定,具有跨省人口流动融合特征;山东半岛城市群与京津冀城市群的人口流动格局联系密切,出现跨城市群人口流动特征;浙江省省域内人口流动特征逐渐加强;长江中游、海峡西岸城市群仍未形成跨越省界的稳定人口流动社群格局。

The effect of"space-time compression"caused by"space flow"breaks the independent allocation of resources between cities and drives the formation of regionally integrated development pattern,and the organizational structure and operation mechanism of the urban network cannot be separated from the inter-city relationship.Based on Baidu migration big data from October 2021 to September 2022,this paper constructs the intercity population flow network for 366 cities in China.At the node level,a population flow surpassing index is proposed to measure urban centrality and explore the spatial clustering characteristics of urban centrality.At the network community level,the monthly intercity population flow pattern and characteristics of 366 cities are analyzed.The results show that:(1)The population flow surpassing index considering flow direction meets the actual needs of intercity population mobility evaluation for measuring urban centrality and can effectively characterize the centrality of cities in the intercity population flow network.Using Baidu Migration big data from January 2023 to April 2023 after the end of the epidemic for comparison,we found that the central impact on national central city is small due to the prevention and control of COVID-19 transmission;(2)Cities in the intercity population flow network exhibit"High-High(HH)"and"Low-Low(LL)"agglomeration characteristics according to their centrality.HH clustering areas are formed in the eastern coastal and central regions,while LL clustering areas are mainly located at the edge of the Qinghai Tibet Plateau,the edge of the three northeastern provinces,and some areas in Hainan Island;(3)The intercity population flow pattern shows different characteristics in different months due to the influence of holidays,COVID-19 transmission,etc.,generally in accordance with the first law of geography,and exhibits provincial differentiation characteristics;(4)The finding of urban cohesive subgroups shows that the intercity population flow patterns of Chengdu-Chongqing Urban Agglomeration,Greater Bay Area,Central Plains Urban Agglomeration,Guanzhong Plain Urban Agglomeration,Yangtze River Delta Urban Agglomeration,and other urban clusters are relatively stable,characterized by cross-provincial population flow integration.The Shandong Peninsula Urban Agglomeration and the Beijing-Tianjin-Hebei Urban Agglomeration have close connection in intercity population flow patterns,characterized by cross-urban cluster intercity population flow.The intercity population flow pattern within Zhejiang Province is gradually enhanced,and the urban clusters in middle reaches of Yangtze River and the west bank of the Taiwan Strait haven’t yet formed a stable population flow pattern across provincial borders.