Exploring the supply-demand match and drivers of blue-green spaces cooling in Wuhan Metropolis

This study explores the spatial evolution and driving factors of cooling supply and demand matching in blue-green spaces (BGSs) to alleviate urban heat island effects. Using Wuhan Metropolis as a case study, the cooling supply index (CSI) and cooling demand index (CDI) were utilized to assess the BGSs' cooling supply capacity and demand levels in 2014, 2018 and 2022. The relationship between them was then examined applying spatial gradient analysis and constraint effect analysis. Subsequently, the coupled coordination degree (CCD) of cooling supply-demand and its built environment-driven explanatory power was investigated. Ultimately, areas with supply-demand mismatches were identified, and tailored cooling strategies were devised to rectify these discrepancies. The results indicated that: (1) Wuhan Metropolis experienced a decline in BGSs' cooling supply capacity and an increase in cooling demand level between 2014 and 2022. (2) There is a significant correlation between the cooling supply capacity and demand level of BGSs in Wuhan Metropolis, with a spatial gradient effect and a constraint effect (CSI values = 0–0.2). (3) The CCD of cooling supply-demand in Wuhan Metropolis decreased from 2014 to 2022, with building density being the dominant built environment factors (q-value = 0.83–0.86). (4) The number of mismatched cooling supply-demand units significantly increased in Wuhan Metropolis from 2014 to 2022, indicating an imperative need to alleviate urban high temperatures. To address this issue, the study proposes a mismatch mechanism-based regulatory strategy aimed at mitigating the heat from residential, transportation, and industrial areas.