Evapotranspiration Estimation using Geo-Spatial Techniques

Water is one of the most critical resources for human life and survival. Increasing population and existing climate change scenario is posing a major challenge to the global fresh water resource. This challenge is more visible in agriculture sector, especially of water stressed countries, as it is often the biggest user of fresh water supplies. India is a classic case of this unfolding scenario. India is already categorized as water stressed country in terms of per capita freshwater availability (1,720 cubic meters in 2019). Out of the 4 per cent share of global freshwater availability in India, almost 78% share of water is consumed by the agriculture sector. UN Population shows that India will be most populous country on this planet surpassing China by 2024. Evapo-transpiration (ET) is a component of Hydrologic Cycle through which most of the water is lost to the atmosphere. Few research papers suggest that the average ET rates of rice were 2.8–5.7 mm/day during the first crop season (May–September) and 6.2–9.1 mm/day during the second crop season (September–January). ET varies spatially and temporally, it can be better understood using Geospatial data. By reviewing all the available ET data in public domain, it is understood that ET is available in coarse resolution. The goal of this project is to estimate Evapo-transpiration. It is derived using the Simplified Surface Energy Balance (SSEB) model, which is now parameterized for operational applications, renamed as SSEBop. The innovative aspect of the SSEBop is that it uses predefined boundary conditions that are unique to each pixel for the “hot� and “cold� reference using multi-spectral satellite imagery of Landsat-8, 30m spatial resolution for mapping ET. The study can successfully delineate the areas of low and high ET. The derived ET data would be useful for various applications such as assessment of water productivity.