Revealing the spatiotemporal characteristics and drivers of the block-scale thermal environment near a large river: Evidences from Shanghai, China

Abstract

Urban rivers play an important role in mitigating surrounding temperatures but empirical research on the thermal environment near large rivers remains sparse and the influencing factors are still unclear. In this study, mobile measurement of the air temperature (Ta) was conducted in summer (July 2021) and winter (December 2021 and January 2022) in an urban area near Huangpu River in Shanghai, China. Four factors: river proximity, ventilation, urban morphology and land use were considered as the potential drivers. A GeoDetector Model (GDM) was used to investigate the contributions of these drivers and their interactions for the uneven distribution of Ta. This study identified that in both seasons, the Ta distribution at block scale showed spatiotemporal variation and exhibited different degrees of stratified heterogeneity at the levels of four potential drivers. Enhancements were found between pairs among the drivers, with maximum explanatory power reaching 96% and 82% for the summer and winter Ta distributions, respectively, suggesting that the thermal environment of the riverfront is driven by a combination of factors. The dominant factors include river proximity, urban morphology and land use, and the urban morphology factor can strongly influence the regulation effect of the river. Moreover, the design of the riverfront open space was also found to have a non-negligible influence. Therefore, it is suggested to consider the dominant factors as well as the interaction between factors according to the target time. Findings in this study give insights for the practice of climate adaptive planning and design on urban riverfront.