Understanding urban atmospheric variability: Implications of vegetation (canopy cover) dynamics in Assam's urban landscapes

Abstract

Large-scale urbanization has altered city surface characteristics, significantly affecting heat balance and thermal environments. The role of vegetative and urban canopy cover in shaping metropolitan climates has gained considerable attention.This study examines the impact of tree canopy cover on thermal comfort and microclimatic conditions in Guwahati, Assam. Conducted in a high-temperature, high-humidity region, it uses qualitative surveys and microclimatic measurements, alongside remote sensing data from 1981 to 2022. Findings show that without canopy cover, car roof temperatures reach 26.32 °C, while areas with high canopy coverage have lower temperatures of 21.17 °C. Vegetation analysis reveals a 10.06% decline in canopy cover, a 13.46% increase in built-up areas, and a 3.85% decrease in open spaces. A negative correlation between NDVI and LST confirms that reduced vegetation increases surface temperatures.The study confirms a negative correlation between NDVI and LST, with coefficients ranging from −.468 to −.224, showing that reduced vegetation increases surface temperatures. Areas with high tree canopy cover experience significant microclimate benefits, with afternoon air and mean radiant temperatures lowered by up to 4.9 °C and 5.48 °C, respectively. Stations with more canopy cover provide greater cooling effects, especially at noon, compared to areas without tree shade.Increasing tree canopy coverage enhances thermal comfort and supports sustainable urban planning. This study offers valuable insights for managing thermal environments and guiding urban policy and sustainable development.