Regulation of urban morphology on thermal environment across global cities

Abstract

Urban morphology (UM) significantly alters the urban thermal environment (UTE), but a comprehensive understanding of the spatiotemporal variations of UM and its contribution to the UTE on a global scale is lacking. To address this gap, this study took 7644 global cities as the study area and applied satellite imagery and global human settlement layer data from 2018 to 2020 to evaluate the UM variations across global cities. Then, this study quantified the UTE by calculating the surface urban heat island intensity, and finally examined the relationship and contributions of UM metrics to the UTE using multiple regression and random forest model. The results reveal significant disparities in UM across global cities, with higher levels of landscape diversity and fragmentation, simpler urban shape, less continuity and aggregation in Asian and North American cities. Two-dimensional landscape configuration is found to have the greatest influence on the UTE (39.6%), followed by landscape composition (COMP) (32.1%), 3D configuration (19.3%), and urbanization (9.1%). However, in tropical and arid zones, COMP has the greatest influence. These findings provide valuable insights into global landscape patterns, and may help to design strategies to mitigate the urban thermal environment.