Quantifying Urban Impacts on Surface Energy and Water Budget over Indian Cities

Rapid urbanization in India has resulted in extensive conversion of natural and agricultural land into impervious surfaces, altering surface energy and water budgets and resulting in the intensification of urban heat island and flood risks. However, most land surface models either consider cities as natural vegetation or rely on simplified urban parameterizations, leading to large uncertainties in simulating urban hydro-climatic processes. In this study, we develop an integrated physics-based framework by coupling an urban module with the Variable Infiltration Capacity (VIC) model to explicitly represent urban canyons, building morphology, and associated physical processes across Tier-I and Tier-II Indian cities. The framework integrates multiple large-scale datasets, including meteorological forcing, hydrological observations, satellite products, and building-height information from the Global Human Settlement Layer and Google-Microsoft Buildings data. Model simulations are evaluated against MODIS land surface temperature and observed streamflow from the Central Water Commission, and sensitivity analyses are performed to identify key urban controls on hydro-thermal responses. The results provide a robust basis for quantifying urban-induced modifications to energy and water fluxes and offer actionable insights for assessing heat and flood risks to support climate-resilient urban planning in Indian cities.