Robustness assessment of urban cold island network based on green infrastructure-A case study of Bengbu, China

Green infrastructure(GI) is important vehicle for mitigating urban heat islands(UHIs), and cold island areas can have real cooling effect on urban surface heat. Research on structural cooling strategies using GI network landscape connectivity as an entry point has gradually become a research hotspot; however, research lacks on enhancing GI cooling efficiency (cold island patch cooling effectiveness utilization or potential development) and dynamic construction adaptability. Tthe stability of a UCI network (UCIN) structure based on GI in different contexts can effectively enhance the efficiency and resilience of urban thermal environment regulations. This study considered the typical city of Bengbu and proposes an urban thermal environment research framework based on the robustness of UCINs, and land use and land surface temperature (LST) data, We extracted the core patches of GI by morphological spatial pattern analysis and screened UCI attributes to determine the UCIN source, constructed the resistance surface of thermal environment with the help of LST characteristics of land use, extracted UCIN corridors by the minimum cumulative resistance, and constructed the UCIN based on GI (GIUCIN) in the mode of "source-corridor". On this basis, the robustness characteristics of the UCIN were simulated with the help of multi-scenario network destruction experiments, the space to maintain the robustness of the UCIN structure was clarified, and the development and protection strategy of urban land classification to maintain the efficient and stable cooling effect of the GI-UCIN was proposed. The study shows that: (1) GI in Bengbu is the primary component of the UCI space, which can effectively break the spatial continuity of UHI patches; (2) GI-UCIN has the characteristics of a hollow outer dense circular structure and (3) the top 20% of GIUCIN source nodes in the centrality ranking are key nodes in maintaining the effectiveness of the GI-UCIN. The results can provides a quantitative basis for determining the policy application point of GI development and protection oriented toward improvement of UHI; simultaneously, the research method can provides a new idea for urban cooling strategies, and further connect with urban planning and management.