Surface-type-dependent deformation in a reclaimed coastal campus revealed by PS-InSAR: A case study of persistent heterogeneity and limited climatic influence.

Ground deformation in coastal reclaimed areas poses significant risks to infrastructure stability and urban sustainability. This study investigates spatiotemporal deformation patterns within a reclaimed coastal urban environment represented by a university campus in Wenzhou, eastern China, using Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) based on Sentinel-1 data. Unlike previous InSAR studies that mainly focused on regional-scale deformation patterns or broad land-use categories, this study investigates deformation heterogeneity among engineered surface types at the intra-urban scale, including roads, playgrounds, and building areas. The results reveal pronounced deformation heterogeneity among different surface types. Roads and playgrounds exhibit similar and persistent subsidence behavior, with average deformation rates of approximately -21 mm/year, whereas building areas show substantially weaker overall deformation and greater local variability. These differences are consistently reflected in both spatial distribution and temporal evolution patterns, demonstrating persistent contrasts among surface types throughout the observation period. To evaluate whether short-term deformation variability is associated with meteorological conditions, temperature and precipitation data were compared with detrended deformation time series using correlation and lag-correlation analyses. Although several temperature variables exhibit statistically significant relationships with deformation for specific surface types and lag periods, these relationships are generally weak and inconsistent. Similarly, precipitation shows only weak and surface-dependent associations with deformation anomalies. Therefore, the meteorological variables examined in this study cannot adequately explain the pronounced deformation differences observed among engineered surface types. Overall, the results demonstrate that surface-type differentiation provides an important perspective for interpreting deformation heterogeneity in reclaimed urban environments. The findings contribute to a better understanding of deformation variability among engineered urban surfaces and highlight the importance of considering surface characteristics in local-scale subsidence assessment.