Research Projects

Evapotranspiration including evaporation from bare soil, transpiration and interception loss from canopy is a key hydrologic variable in the terrestrial water balance impacting sectors like agricultural production and ecosystem health. The variation in ET is dependent on a plethora of factors like land-use type, vegetation, topography, climate and local meteorological conditions. Given the complexity associated with ET, further heightened by changes in the global environment, increases the challenges associated with accurate ET estimation. With increasing efforts to create multi-year global gridded products using a multitude of approaches for both historical and future period there is a need to understand where datasets agree and disagree to pinpoint where our collective understanding may fall short. Given the current literature four vital gaps persist within the Indian context, i) quantifying the change in the actual evapotranspiration based on the available projection, ii) assessing the Climate Vulnerability and Risk Analysis of projected ET to observed data, iii) identifying the source of uncertainty in terms of different ET components and iv) assessing the reason for the uncertainty in the ET components in the models, with examining the model parameterization of surface–atmosphere energy and water processes likely contribute to model spread in ET partitioning. This proposal proposes to identify the uncertainty associated with future projections of ET under different climate change scenarios based on the different components of ET at basin scale. The underlying reason or the physical mechanism leading to such large variations will be identified and State-of the art statistical tools will be employed to obtain reliable projected ET products at regional scale over the Indian Subcontinent. Constraining the projections using observed data at fine spatial resolution (basin scale), in an attempt to improve the accuracy of the projections, will improve the estimates of future availability and extremes like flood and drought at a monthly scale. Moreover, it is important to assess the reason for the uncertainty in the estimation of ET from the models – specifically over India. In India, the land-atmospheric feedback plays a crucial role, both for the strength of the Indian summer monsoon and for the development of heatwaves over the nation. However, representation of these processes in the climate models is not adequate. Although, the recently released climate models, i.e., CMIP6 have improved from their predecessors, the uncertainty prevails. Studies mentioned that the uncertainty in the CMIP5 in ET partitioning is strongly linked to model differences in representing the vegetation leaf area index (LAI). These will be comprehensively studied in this work to identify the source of the uncertainty. The outcomes of the project will be shared with the research community through renowned publications and web dissemination of the developed data products.