Decadal Assessment of Urbanization Impacts on Surface Energy Balance and Thermal Dynamics using Remote Sensing data: A Case Study of Ahmedabad, India

Objective: This study investigates the spatiotemporal variations in land use/land cover (LULC), surface temperature, and surface energy flux components in Ahmedabad, India, from 2014 to 2024 Method: using Landsat 8 (OLI/TIR) imagery and the SEBAL (Surface Energy Balance Algorithm for Land) model on the Google Earth Engine (GEE) platform. Findings: Results reveal a significant increase in built-up areas from 27% to 36% and a decline in natural vegetation from 23% to 17%, indicating rapid urban expansion and environmental stress. Land Surface Temperature (LST) increased by 3.16°C over the decade, exhibiting a strong inverse correlation with the Normalized Difference Vegetation Index (NDVI), thereby highlighting the impact of vegetation loss on urban heat amplification. Surface energy flux analysis showed a 7.7% increase in net radiation (Rn) and consistently elevated sensible heat flux (H), particularly in urban cores, while latent heat flux (LE) and evapotranspiration (ET) remained relatively low and confined to vegetated areas. Seasonal comparisons further emphasize higher Rn and H values during summer, with LE peaking in the monsoon due to increased moisture and vegetation activity. Correlation analysis confirmed a strong positive relationship between ET and LE (R2 = 0.780) and a negative correlation with H (R2 = 0.768), underscoring the importance of vegetation in moderating urban microclimates. Novelty: These findings indicate that rapid urbanization intensifies thermal stress and alters surface energy dynamics in the study area, emphasizing the necessity of integrating vegetation-focused climate adaptation measures into urban planning. Future research should validate these findings in situ and extend the approach to other semi-arid cities for broader climate adaptation planning. Keywords: Surface Energy Balance, Remote Sensing, Thermal Dynamics, Urbanization Impacts, Land Use Change