Multiscale impacts of urban nature on land surface temperature over two decades in a city with cloudy and foggy climates

Rapid urbanization intensifies the urban heat island (UHI) effect and increases the frequency of extreme heat events, posing significant risks to urban environments and residents' well-being. While previous research has demonstrated that urban nature, particularly urban green spaces (UGS) and urban blue spaces (UBS), helps mitigate UHI, there is still a limited understanding of the spatiotemporal relationships between urban nature and land surface temperature (LST, an indicator of UHI) in cities with cloudy and foggy climates over many decades. This study leverages remote sensing data and applies the multiscale geographically weighted regression (MGWR) model to analyze the multiscale impacts of urban nature on LST in Chengdu, China, from 2000 to 2020. Our results show a consistent rise in LST levels over this period, alongside a reduction in UGS in both the city center and its surrounding areas. Additionally, urban nature consistently mitigates UHI at local scales over time. The mean coefficients of UGS were - 0.33, -0.28, -0.25, and -0.37 across four periods, while those of UBS were - 0.26, -0.30, -0.28, and - 0.21. These findings provide valuable insights into the multiscale role of urban nature in mitigating UHI, offering evidence to support policymakers in developing nature-based solutions to enhance thermal comfort.