Assessing the Impact of Bhuvan Vegetation Data on the interactions of the Indian Ocean Dipole and ENSO in Earth System Model Simulations/Predictions.

Vegetation cover change is one of the main processes of ecological and environmental changes, which plays a crucial role in the Earth's climate system, influencing both regional and global climate patterns. Hence, in climate models, the representation of the earth surface, including vegetation cover is an essential factor. In the present study, the annual, global gridded land-use states and all associated land-use transitions between those states, fractionally, at 0.25⁰ spatial resolution of the CMIP6 datasets for the years 1950–2100 is used and a new time-varying monthly Vegetation Fraction dataset has been implemented in the IITM-DPS (Decadal Prediction System) using the BHUVAN-NRSC (Indian) satellite data with the aim of producing accurate climate simulations. The incorporation of time-varying vegetation into the Earth System Model (ESM) has led to significant improvements in simulating climatic patterns. The importance of an accurate representation of vegetation on the simulation and forecast of El-Nino Southern Oscillation (ENSO) over the tropical pacific and the Indian Ocean Dipole (IOD) patterns over the Indian ocean has been highlighted. The monthly rainfall anomaly shows that the regional precipitation patterns over India and the annual cycle are accurately represented by the ESM. Experiments with and without BHUVAN data highlights the significant contribution of regional vegetation fraction in simulating the monsoon features. Results indicate that the time-varying vegetation fraction from BHUVAN data measurably improves the simulations of Indian summer monsoon rainfall compared to climatological vegetation fraction thereby highlighting the need of such regional vegetation data for accurate forecasting.