Multi-dimensional intercity linkages, industrial structure, and their cross-level interactive effects on impervious surface expansion: Evidence from Beijing-Tianjin-Hebei, China

Regional integration is reshaping urban spatial patterns by strengthening intercity linkages and fostering cross-level interactions among influencing factors. Yet the interactive effects of these multilevel factors under regional integration remain poorly understood. To address this gap, this study used geospatial big data to quantify intercity linkage intensities across five dimensions—population mobility, information flow, transportation connectivity, capital linkage, and regional cooperation—in the Beijing–Tianjin–Hebei urban agglomeration. A hierarchical generalized linear model (HGLM) was then constructed across the pixel, county, and city levels to examine the associations of multilevel factors and their cross-level interactions with impervious surface expansion from 2012 to 2022. The results showed that the interaction between information flow and secondary industry share, and that between transportation connectivity and tertiary industry share, were negatively associated with impervious surface expansion, whereas the interaction between capital linkage and secondary industry share showed a positive association. Furthermore, interactions between industrial development and population mobility, transportation connectivity, and regional cooperation were associated with a higher probability of peri-urban expansion, while stronger capital linkage combined with industrial development was associated with impervious surface expansion near urban cores. These findings advance the understanding of impervious surface expansion under regional integration and offer policy insights for optimizing spatial structure and balancing core-periphery dynamics.