Inter- and intra-LCZ thermal heterogeneity: The dominant role of external environments in shaping local land surface temperature

Abstract

In light of escalating urbanization and climate change, understanding the Urban Heat Island (UHI) effect is crucial to improving urban resilience. The Local Climate Zones (LCZs) classification, introduced in 2012, has become a vital tool in urban climate research. While most studies focus on inter-LCZ heterogeneity (temperature differences between LCZ types), this study highlights the less-explored intra-LCZ heterogeneity (variations within the same LCZ type). Using ECOSTRESS LST data, we examine spatial and diurnal LST variations in Fuzhou, China—a representative “Furnace City”. Random Forest models and Shapley values analysis reveal that external factors, such as distance to the city center and proximity to hotspots (like LCZ 3 or 8) or blue–green infrastructure, play significant roles in both inter- and intra-LCZ LST variability. Water bodies typically lower surrounding daytime temperatures but increase them at night, while greenery consistently mitigates surrounding LST throughout the day. Our findings suggest that applying the LCZ framework requires not only attention to local ( 100 m) surface properties but also consideration of neighborhood and city-scale characteristics to better capture the spatio-temporal heterogeneity of urban thermal environments. These insights emphasize the need for urban planning strategies that integrate blue–green infrastructure and manage thermal hotspots to mitigate UHI effects.