Spatiotemporal differences and influencing factors of urban vitality and urban expansion coupling coordination in the Pearl River Delta

In the contemporary state of accelerated urbanization in China, urban expansion has become the mainstream trend of urban development. However, in the context of urban expansion, whether coordinated development between urban expansion and urban vitality is achieved is an important concern facing the current urban expansion process. The Pearl River Delta (PRD) urban agglomeration is a hotspot of rapid economic development in China, and it is essential to examine the coupling relationship between the region’s urban dynamics and urban expansion to promote rational urban development. This study analyzes the dynamics and evolutionary characteristics of urban expansion based on multisource nighttime light data, employing an UERI and other methods. We apply the entropy method and coupling coordination model to evaluate urban vitality and conduct a coupling analysis of urban expansion and urban vitality from 1992 to 2021. The results show that during the study period, the urban built-up area of the PRD urban agglomeration increased by 61,131.59 km 2, urban vitality gradually increased each year, the coupling coordination between urban vitality and urban expansion gradually increased, and factors such as economic development, urban planning, and geographical location advantages also influenced changes in urban vitality and urban expansion and their coupling and coordination in the study area. This study provides a methodological reference and data support for the investigating the spatiotemporal evolution of urban agglomerations and urban vitality analysis.