Impacts and Spatiotemporal Differentiation of Built Environments on the Urban Heat Island Effect in Cold-Climate Cities Based on Local Climate Zones

Urbanization has increased the surface urban heat island (SUHI) effect. This study uses local climate zones (LCZ) and urban built environment characteristics (UBECs) to explore the factors influencing land surface temperature (LST) and SUHI in various UBECs in Shenyang, China. Google Earth Engine was used to calculate LST. An LCZ map of Shenyang was created to analyze seasonal differences in the SUHI. A correlation model was used to screen the UBEC, and a geographically and temporally weighted regression (GTWR) model was used to explain the spatial variations in the urban heat environment caused by built environments in different seasons. Compared to traditional methods, the GTWR model exhibits better goodness of fit and is more effective in capturing the spatiotemporal heterogeneity of variables. Compact and high-rise areas had higher SUHI effects compared to other LCZs, whereas land-cover LCZs had a cool-island effect. The GTWR model helps planners identify the climatic impacts of each factor in different spatial locations within the study area, as well as variations across seasons. Vegetation-related factors had less impact in densely-built areas, whereas the proportion of blue areas was more effective in alleviating extreme climates in high-density zones. The impact of building density on the heat island effect exhibited substantial spatiotemporal variation, particularly in compact, high-rise LCZs during both seasons. To address extreme winter–summer weather in cold regions, this study examined seasonal SUHIs and their interaction with UBECs, offering strategies and guidance for heat mitigation in urban design.