Mitigation pathways of urban heat islands and simulation of their effectiveness from a perspective of connectivity

Abstract

• Proposed a multi-level network to mitigate urban heat islands . • Constructed resistance surfaces using 2D and 3D urban structural parameters. • Identified critical corridors and nodes through circuit theory. • Validated future urban thermal simulations using the PLUS model. • Assessed the cooling network's effectiveness in mitigating future heat islands. Several studies have proposed strategies to alleviate the urban heat island (UHI) amidst the challenges of global warming and rapid urbanization. Though, few have explored multi-network synergies of heat and cold islands and simulation of their effectiveness. This study constructed an urban thermal environment (UTE) network by 2D and 3D urban structural parameters from a perspective of connectivity. Cooling measures are proposed to mitigate the UHI by combining forward and reverse thinking. The thermal environment is simulated using the patch-generating land use simulation (PLUS) model to assess the effectiveness of the cooling network. Firstly, morphological spatial pattern analysis (MSPA) and connectivity analysis are used to identify urban cold and heat island sources. Then, thermal resistance is constructed by 2D and 3D structural parameters. A multi-level thermal environment network is generated through the minimum cumulative resistance (MCR) model and circuit theory. Subsequently, key nodes within this network are identified. Finally, the PLUS model simulates and compares the thermal environment before and after the implemented of cooling network. Taking Fuzhou City as an instance, we find that: (1) 43 cold island sources, 28 heat island sources, 196 cooling corridors, 64 heat island corridors, and 711 thermal environment spatial network pinch-points are identified. (2) The PLUS model demonstrates an overall accuracy of 78% in simulating the 2023 thermal environment, affirming the feasibility of UTE simulation. (3) After optimization, the growth rate of the low-temperature zone increased by 60.63% while the growth rate of the high-temperature zone decreased by 8.63%, indicating the effectiveness of the proposed multi-level cooling network in mitigating the UHI. The approach presented in this research provides new insights for sustainable urban development and climate adaptation planning, and is crucial for addressing the UHI.