关键词: 人口迁移网络, 社会网络分析, 重力模型, 长江三角洲

Abstract: The fast flow of various productive assets and power among different places has promoted the formation of city networks in the context of globalization, regionalization and localization. The city network has nowadays become a new mode of regional organization and spatial structure, and imposes a significant influence on the process of regional integration. By applying the social network analysis, this article attempts to investigate the characteristics, emergence and evolution of human mobility networks in the Yangtze River Delta region. The density, centralization and connectedness of the networks are calculated, and the results show that the human mobility networks in this region have formed and are characteristics of spatial unbalance in population distribution. Secondly, cities including Shanghai, Hangzhou, Nanjing, Ningbo and Suzhou-Wuxi-Changzhou areas have constituted important nodes of population agglomeration. Meanwhile, these cities are experiencing the process of emigration of population to other adjacent areas. Thirdly, two modes of human mobility networks, inter-province network and intra-province network, coexist in the Yangtze River Delta region. Specifically speaking, the inter-province network is characteristic of hierarchical diffusion, and the migration of population mainly occurs among Wuxi, Suzhou and Hangzhou. However, the intra-province network becomes more complex and can be further categorized two models—Jiangsu's intra-province network and Zhejiang's intra-province network. From the perspective of the spatial pattern, Jiangsu's intra-province network is characteristic of adjacent infiltration which means the relocation of population from population cores to peripheral areas. However, Zhejiang's intra-province network exhibits a hub-and-spoke structure and primarily includes three nodes of population mobility— Hangzhou, Ningbo and Taizhou. Based on the discussion mentioned above, the mechanism of human mobility network is analyzed with the consideration of the effect of employment opportunity, income, industrial structure and mobility cost on the population mobility. The analysis manifests that factors involving the openness of cities, the ratio of secondary industry and tertiary industry, housing price, spatial distance and institutional thickness have significantly affected the formation of human mobility network in the Yangtze River Delta. Finally, this article proposes a theoretical hypothesis of the evolution of human mobility network which includes the following four stages—discrete distribution stage, single-core agglomeration stage, multi-center network stage, and chained spatial network stage.

Key words: human mobility network, social network, gravity model, Yangtze River Delta