The creation of multi-level urban ecological cooling network to alleviate the urban heat island effect

In the context of global warming and rapid urbanization, the surface urban heat island (UHI) effect has become increasingly serious. Research on UHI effect mitigation can provide useful references for urban planners and decision-makers, and is of great significance for sustainable urban development. However, few studies have considered UHI mitigation from a network perspective, not to mention the multi-level network. Therefore, oriented to the practical needs of urban master planning, this study took Hefei city as a case study, combined the methods of morphological spatial pattern analysis (MSPA), landscape connectivity analysis and circuit theory, and proposed a new approach for UHI mitigation by creating the ecological cooling network at multi-level. The results showed that: (1) 19 heat source patches and 24 cold source patches were identified, which were mainly distributed in the main urban area and the suburbs, respectively. (2) The central urban area had higher resistance values to the diffusion process of hot and cold air flow than the surrounding areas. (3) 71 corridors and 46 barrier points between cold-heat sources were obtained at metropolitan level, while 41 corridors and 70 pinch points between heat-heat sources were obtained at main urban area level. (4) The UHI effect can be potentially alleviated by strengthening the connectivity of cold-heat sources and breaking the connectivity of heat-heat sources. The approach proposed in this research can provide new insights for the compilation of climate-resilient urban planning and the formulation of UHI mitigation strategies.