Scale-dependent thermal responses to urban land-use transitions: evidence from Shanghai

Urban land use/land cover (LULC) change continuously reshapes surface thermal environments, yet the thermal responses of specific transition pathways across spatial scales remain insufficiently understood. Using Shanghai as a case study, this study integrates Landsat imagery from 2000, 2010, 2017 and 2024 with land-use transition matrices and a multi-scale grid framework to examine transition-specific thermal responses and their scale effects. Results show that Cropland → Impervious remained the dominant transition, decreasing from over 1300 km² in 2000–2010 to about 480 km² in 2010–2017 and 350 km² in 2017–2024. Construction-related transitions generally produced stronger thermal responses, whereas transitions involving green space, wetlands or water bodies more often showed weak warming, weak cooling or localized cooling. As the scale became finer, ΔLST distributions converged and extreme values declined. These findings reveal that urban thermal responses are jointly shaped by transition type and spatial scale.