Surface urban heat island mitigation network construction utilizing source-sink theory and local climate zones

Negative impacts of urban heat island (UHI) are exacerbated by rapid urbanization. To address insufficient on construction of key areas for UHI mitigation, source-sink theory and local climate zone (LCZ) were developed to build networks. This study discriminated source and sink landscapes, and applied multiple spatial analyzes to identify key surfaces, corridors and barrier points of heat source and sink landscapes at urban and main urban district scales. 30 important heat source and sink landscape surfaces were identified, primarily comprised open high-rise and open mid-rise in heat source landscapes, accounting for 34.07%, 22.19% at urban scale, and 48.63%, 29.68% at main urban scale, composed of low plants and water in heat sink landscapes, representing 68.63%, 12.28%, and 45.99%, 31.80%, respectively. 62 and 58 heat source corridors identified were dominated by open high-rise, and low plants, accounting for 16.02%, 31.67%, and 21.70%, 22.41%. 60 and 46 heat sink corridors identified composed of open high-rise, low plants, and water, with percentages of 19.94%, 41.13%, 13.25%, and 32.97%, 30.09%, 7.42%, respectively. Barrier points of 38 and 28 heat source landscapes identified were characterized mainly by low plants, and water, representing proportions of 52.10%, 20.24%, and 42.73%, 18.31%, respectively. Barrier points of 41 and 20 heat sink landscapes identified were primarily associated with open high-rise, open mid-rise accounting for proportions of 41.17%, 20.03%, and 54.17%, 18.89%, respectively. Given these key areas, it is recommended to split heat source landscape, increase area of smaller sink landscape, renew of LCZs to those with lower UHI intensity.