Spatiotemporal Evolution of Urban Thermal Conditions, Vegetation Dynamics, and Built-up Expansion in Ahmedabad, India (2000–2025) Using Multi-Temporal Landsat Analysis.

Stephen Antheny Mekwan

Rapid urban expansion has substantially altered urban thermal conditions across many semi-arid cities. This study examined spatiotemporal variation in land surface temperature (LST), vegetation cover, and built-up intensity across Ahmedabad, India, between 2000 and 2025 using multi-temporal Landsat imagery and the Google Earth Engine (GEE) platform. Spatial analysis revealed progressive expansion of high-temperature urban zones and increasing intra-urban thermal heterogeneity, particularly across densely urbanised eastern and central sectors of the city. Mean LST increased from 46.11°C in 2000 to 51.60°C in 2020 before declining during the 2025 acquisition period. Regression and correlation analyses indicated persistent negative relationships between vegetation cover and LST, whereas built-up intensity remained positively associated with elevated thermal conditions. Temporal analyses further suggested increasingly heterogeneous vegetation-temperature relationships through time, with later years exhibiting broader thermal variability across comparable NDVI ranges despite localised increases in vegetation cover. The final multivariate regression model explained substantial variation in LST (Adjusted R² = 0.690). Overall, the findings indicate that continued urban expansion in Ahmedabad was associated with increasingly heterogeneous urban thermal conditions and changing vegetation-temperature relationships across the metropolitan region, highlighting the importance of ecological continuity and spatial vegetation distribution in climate-sensitive urban planning within rapidly urbanising semi-arid cities.