Spatial and seasonal differences between near surface air temperature and land surface temperature for Urban Heat Island effect assessment

In the context of global warming, urban thermal environments are a growing concern. Previous studies focused on Urban heat island effect and global warming mitigation amplitude with Land Surface Temperature (LST), ignoring the interaction of LST and Surface Air Temperature (SAT), which comprehensively affects pedestrian thermal comfort. This study examines the SAT-LST relationship to reduce the uncertainty about SAT prediction based on LST. Utilizing data from 280 air temperature sensors and Landsat satellite remote sensing, we quantified temporal and spatial variations between SAT and LST in Changsha (under a monsoon climate). Analyzing data from 2018 to 2022, the study found that: 1) There are spatiotemporal differences in the SAT-LST relationship, with strong spatial heterogeneity, notably in urban areas and during the summer; 2) A stronger correlation between SAT and LST in winter (R2 = 0.916, RMSE = 1.242 °C) than in summer (R2 = 0.500, RMSE = 1.517 °C); 3) UHI and SUHI also exhibit spatiotemporal variations, with the cold and hot spots in summer not completely overlapping spatially. By constructing an SAT-LST regression model, the study deepens the understanding of the quantitative relationships between SAT and LST, thus contributing to urban thermal environment research and climate adaptive urban planning and design.