Spatio-temporal Variation Analysis of Thermal Climate in Response to Urban Cover Changes: A Case Study of Delhi Using Landsat Data

Abstract

ABSTRACT Urbanization and changes in Land Use Land Cover (LULC) influence the formation of urban microclimate (UMC). The current study analysed the urbanization and microclimatic changes in the National Capital Territory (NCT) of Delhi utilizing the Landsat-derived LULC map, Land Surface Temperature (LST), and a variety of spectral indices viz., Heat Effect Contribution Index (HECI), Surface Urban Heat Island (SUHI), Thermal Index (TI) and Environment Criticality Index (ECI). The results indicate that Delhi has undergone a substantial increase in urbanization and concomitant urban warming (1999–2021). The mean LST had risen across all LULC classes, with vegetation exhibiting the most significant variance in mean LST. Largely, water bodies and vegetation lands converted to other LULC classes yielded the highest rise in LST. Notably, the contribution of the build-up to the heat effect rose by more than 40%. A rise in LST and its association with different LULC classes led to the widespread development and spatiotemporal shifting of SUHI and a subsequent decline in thermal comfort. This research uniquely quantifies LST changes associated with shifts in LULC categories and utilizes multiple heat indices to study the UMC of Delhi, offering crucial insights for future planning and policy formulation.