Customized cooling design scheme for diversified local climate zones to accommodate urban spatial heterogeneity

Effective urban cooling designs are becoming increasingly important for addressing urban expansion and climate change. However, previous studies tended to develop universal cooling designs, which were limited by their effectiveness and necessity in urban regions with heterogeneous spaces. Taking Shanghai, China, as a case, this study aimed to develop a systematic cooling design scheme accommodating urban spatial heterogeneity based on the thermal effects of urban design indices in spaces with different morphological features. Through the introduction of an expanded local climate zone (LCZ) scheme, remote sensing and numerical simulations were used to analyze the thermal effects of seven design indices on 14 built-up LCZ classes. The cooling performances of LCZ design scenarios with various coverage ratios of trees, grasslands, and reflective pavements were evaluated, and a systematic cooling design scheme was developed accordingly to achieve moderate temperatures for each LCZ class. The results indicated that the thermal effects of the design indices depended on local spatial morphology, including the building footprint ratio, mean building height, and sky view factor. Various cover ratios of trees and grasslands were customized for each LCZ class for necessary cooling, and three optional strategies were recommended according to LCZ morphology for supplementary cooling. The application of the cooling design scheme in Shanghai highlighted that 65.3 % of the built-up LCZs required cooling strategies. This study can support policymakers in developing effective cooling strategies to mitigate the heat islands in urban regions with heterogeneous spaces.