Impacts of coordinated development policies on urban heat islands in the Beijing-Tianjin-Hebei urban agglomeration, China

The accelerated process of urbanization has led to a crisis in the urban thermal environment, giving rise to the urban heat island (UHI) phenomenon. During summer, the UHI is compounded by heat waves, exacerbating heat stress. We utilized MODIS and Landsat images to extract surface temperature data during summer in the Beijing-Tianjin-Hebei urban agglomeration (BTH) from 2000 to 2021 in China. By employing spatial autocorrelation with Getis-Ord Gi*, we automatically classified the intensities of heat islands, enabling us to explore the spatial and temporal variations in the UHI and its influencing factors. Our findings revealed the following: (1) Between 2000 and 2021, the overall UHI experienced a 7.26% increase, and a pronounced polarization was observed, characterized by a prevalence of more intense heat and cold islands. (2) The UHI was more influenced by the interplay of anthropogenic factors, with notable contributions from impervious surfaces (16.03%), population (15.06%), and energy consumption (14.88%). (3) Co-development policies enhanced the UHI, of which the components of Residential (0.432), Public facilities (0.421) and Enterprise(0.391) were major promoters. In conclusion, this study significantly advances our understanding of UHI in urban agglomerations and holds great significance for sustainable development planning.