Port-city dynamics and coupling relationships in China

Port-city dynamics are significantly affected by international maritime shipping and investment linkages. Container shipping and corporate investment networks exhibit complex embedded interactions and reciprocal feedback relationships in coastal port systems. To analyze port-city evolution, this study introduces an indicator model. The model is constructed on a “directed network” model, utilizing data from container liner shipping and port corporate investment links in 2016 and 2021. The model incorporates Directed Acyclic Centrality (DAC), Dominant Agent Power (DAP), and Comprehensive Distribution Ability (CDA) to analyze the trend and function of each network independently and the coupling relationships between them. The effects of shocks in one network on the other are measured utilizing the Vector Autoregression Model (VAR). The findings are fourfold. Firstly, the shipping and investment networks displayed a significant increase in both scale and density throughout the study period. The distribution of in-degree and out-degree centrality among network nodes demonstrates a significant imbalance, alongside an increased degree of polarization. Secondly, the spatial development of the shipping network indicates a move towards stronger integration between regional clusters . In comparison, the investment network has evolved into a hierarchical core-periphery structure. Thirdly, the coupling between the two networks has intensified, accompanied by a reduction in ports exhibiting low coupling. In addition, the types of coupling have become more diverse, resulting in a more optimized structure. Finally, VAR analysis shows that the DAP of the shipping network and the out-degree and in-degree centrality of the investment network, are crucial factors influencing CDA. • A directed network system for container shipping and corporate investment is constructed. • Imbalances and asymmetries in port flow relationships are identified. • A metric model for analyzing port-city dynamic evolution is introduced. • Dual-spiral coupling relationships of port-city networks based on physical and virtual flows are researched. • The dynamic evolution of port cities is explored through multi-dimensional connections and multi-port interactions.