Impacts of land use, vegetation, and air pollution on surface urban heat island spatiotemporal dynamics: Tehran as a case study

Abstract

Urbanization significantly influences local climate conditions, particularly through the intensification of the Surface Urban Heat Island (SUHI) effect. Understanding the spatial and temporal variations in SUHI is essential for effective urban planning and environmental management. This study investigated the dynamics of SUHI in Tehran, examining its correlations with land surface temperature (LST), vegetation coverage, land use/land cover, and air pollution parameters. Using a comprehensive methodological framework including Ordinary Least Squares (OLS), Geographically Weighted Regression (GWR), Moran’s I, and hotspot analyses, the research analyzed temporal and spatial variations in urban climate patterns. The results demonstrated that barren lands exhibited the highest daily average LST (42.62 °C) and lowest (36.72 °C), while forest parks and grasslands showed nighttime LST ranging from 18.69 to 13.58 °C. Air pollution analysis from to 2018–2021 revealed declining trends in AAI and CO, while NO 2 and O 3 increased (R 2 = 0.65 and 0.23, respectively). A 20 years analysis (2001–2021) showed an upward trend in NDVI (R 2 = 0.33), with stable LST patterns, although urban areas experienced increased nighttime temperatures. The GWR model outperformed OLS in terms of LST prediction accuracy (R 2 = 0.87 day, 0.85, night). Hotspot analysis identified significant LST clustering in the southern regions, whereas the SUHI index showed contrasting day (increasing) and night (decreasing) trends over the study period. Notably, daytime LST correlated strongly with air pollution indices, whereas nighttime LST showed stronger associations with NDVI. These findings highlight the significant impact of urban development and green space reduction on SUHI intensity and air pollution levels in Tehran’s metropolitan areas.

Bibliographic Information