Land-Atmosphere Feedback in Indian Summer Monsoon

Monsoon is traditionally believed to be governed by large scale circulations. Contribution from local land processes was neglected in the state of art studies. Here we show that land contributes quite significantly to the rainfall during the monsoon season in India. The Indo-Gangetic basin and North East India are the two major hot-spot regions of high land-atmosphere feedback. A significant proportion (up to 20%) of the monsoon rainfall over Gangetic Basin and North East India comes from the Evapotranspiration generating from land processes. Experimental simulations of monsoon rainfall with regional land atmosphere model [Weather Research and Forecasting Model- Community Land Model (WRF-CLM)] shows that a change in the land use land cover from forest land to crop land results into a decrease in rainfall. The feedbacks get further intensified with the introduction of irrigation, practiced in India. We further showed that a good representation of land in the regional monsoon models solves the problems of dry bias, which remained unaddressed before the analysis.

About the Speaker:
Subimal Ghosh completed his doctoral studies from IISc, Bengaluru in 2007 along with the best thesis award. Prof. Ghosh works specifically in the areas of Indian Summer Monsoon and its extremes with regional modelling, land atmosphere interactions in the South Asian monsoon regions, improving predictions of monsoon characteristics using innovative dynamic-statistical modelling and assessing impacts of climate variability and changes on water resources in India. He published more than 80 research papers in top journals. He was awarded the Shanti Swarup Bhatnagar Prize 2019 in the Earth, Atmosphere and Planetary Sciences. He is also the recipient of Swarna Jayanti Fellowship. He got the young scientist/ engineer awards from multiple apex Science/ Engineering Academies of India. IIT Bombay has awarded him twice, considering his research contributions and scientific excellence.