Impacts of urban land-use change on land-surface heat exposure risk: spatial evidence from multi-source remote sensing in Zhejiang Province.

Rapid urbanization can intensify land-surface heat exposure by replacing natural surfaces with impervious materials, yet the thermal effects of specific land-cover transitions remain insufficiently understood. We integrated land-cover data for 2000, 2010, and 2020 with summer daytime land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI) data for 2001, 2010, and 2020 to examine land-use change and LST-derived heat exposure across Zhejiang Province, China. Land-cover transition analysis, historical percentile-based heat-exposure identification, and regression models were applied. From 2000 to 2020, impervious surfaces expanded by 137.94%, with cropland accounting for 86.10% of newly added impervious surfaces. Mean summer daytime LST increased from 28.59 to 30.47 °C, while the 95th percentile increased from 31.45 to 36.09 °C. Newly added impervious surfaces exhibited the greatest warming (4.57 °C) and highest heat-exposure ratio (90.36%), whereas stable forestland showed the lowest warming (1.18 °C) and exposure ratio (9.24%). At the prefecture level, newly added impervious surfaces were positively associated with heat exposure (R 2 = 0.69), while NDVI was negatively associated with LST warming (R 2 = 0.81). Impervious-surface expansion and ecological buffering jointly shaped land-surface heat-exposure risk. Limiting heat-intensive land conversion and strengthening blue-green infrastructure in newly urbanized areas can support climate-adaptive spatial planning. These results represent an LST-derived public heat-risk proxy rather than directly observed health outcomes.