Investigating the Coupling of Supply and Demand for Urban Blue and Green Spaces' Cooling Effects in Shandong, China

It is of great significance to determine the level of demand for thermal environment regulation and the availability of blue-green spaces for thermal environment regulation to alleviate the effects of urban heat islands. Taking Shandong Province, China, as the study area, combined multi-source remote sensing data are used in this study to construct the index system of cold island supply capacity (CIS) and the cold island demand level (CID). We use the methods of spatial regression, quadrant division, and coupling coordination degree to analyze the correlation, matching status, and the level of coordinated development between the supply capacity and demand for the cooling effect. We also explore the change law and spatial characteristics of the blue-green spaces' cooling effects supply and demand matching. Results show that: (1) The CIS and the CID are significantly negatively correlated and spatially heterogeneous in distribution, with a significant spatial spillover effect. (2) The dominant type of supply and demand is one of low supply and high demand, which means that the supply and demand for cool islands' cooling effect are unbalanced, with significant problems of spatial mismatch and quantitative imbalance. (3) The coupling between supply capacity and demand level is on the verge of becoming dysfunctional because the uneven distribution of urban buildings, population, and blue-green spaces reduce the coupling between supply and demand levels. This research can provide a new perspective and scientific basis for the study of the cooling effects of blue and green spaces and the mitigation of the heat island effect in densely populated urban centers.