Surface Energy Partitioning and Land–Atmosphere Interactions in Diverse Indian Agro-Climatic Regions

The Indian monsoon contributes over 80% of India’s annual rainfall between June and September, sustaining agriculture, water resources, and the livelihoods of over a billion people. Understanding how land surface processes regulate monsoon behaviour is crucial for improving climate prediction, irrigation efficiency, and long-term food and water security. This study investigates surface energy and water fluxes across two contrasting agro-ecosystems of India. Continuous measurements of sensible and latent heat fluxes, net radiation, and soil heat flux were analysed to assess dynamic land–atmosphere exchanges under varying vegetation and monsoon conditions. This research explores these processes across two representative ecosystems using integrated ground-based and satellite observations. Physical models were applied to estimate soil heat flux using day–night land surface temperature (LST), NDVI, soil texture, and soil moisture data. Higher evaporative fractions (0.7–0.9) during the monsoon over croplands compared to lower values (0.05–0.4) in arid grasslands reflected stronger coupling under moist and vegetated conditions. Satellite data from ECOSTRESS, MODIS, and LANDSAT were integrated to estimate farm-scale evapotranspiration (ET), showing strong validation (R² = 0.87; RMSE < 0.21 mm/day). The outcomes support ISRO’s TRISHNA and Earth Observation missions, emphasising the One Drop, One Crop approach and offering advisory insights for farmers to improve water budgeting, irrigation efficiency, climate-resilient, and sustainable agriculture across diverse Indian landscapes.