SUHI evolution characteristics and influencing mechanism of eight furnace cities in middle and lower reaches of Yangtze River, China

The surface urban heat island (SUHI) effect poses severe challenges to urban sustainable development and urban livability. Current studies lack the analysis of heat island effect from the perspective of new and old furnace cities. In this study, spatiotemporal characteristics and influencing mechanisms of heat islands were investigated in eight furnace cities in middle and lower reaches of Yangtze River from 2010 to 2020. DBSCAN was proven effective in exploring the number and location of heat island cores. Besides, MGWR model was utilized to analyze the spatial heterogeneity of dominant factors. The results indicate that: (1) The area of heat islands showed an increasing trend. The increase rate in new furnace cities was faster than that in the old. (2) The heat island patches had gradually gathered. The heat island cores of eight furnace cities showed three types of growing, stabilizing, and decreasing. (3) The expansion type of heat islands was mainly edge expansion. The transformation of farmland into built-up land made the most significant contribution. (4) Impervious surface area, gross domestic product, and population density were the top three factors intensifying the SUHI effect. The results can provide a scientific basis for formulating reasonable urban heat island mitigation strategies.