Somnath's primary research area is modeling land-atmosphere interactions, where he builds and uses models to study the effects of vegetation dynamics and land-use/land-cover change like deforestation and agriculture on regional weather and climate. This work has implications for regional climate change, food security, biological carbon sequestration, and carbon accounting. He also works on renewable energy meteorology, including resource assessment, forecasting, and impact assessment for the wind and solar energy sectors. Somnath's research has been funded by US NSF, NASA, ISRO, DRDO, SERB, and a number of private corporations.
He is the Chief Editor of Earth System Dynamics, a leading journal of the European Geosciences Union (EGU), and a co-convenor of Energy Meteorology at the EGU General Assembly. He is also the Professor-in-Charge of the IIT Delhi Sonipat campus. He serves on various committees at IIT Delhi, including the IITD Initiative for Gender Equity and Sensitization and the Budget Allocation and Monitoring Committee. He is a Founding Director of Tensor Dynamics, a weather and climate analytics start-up incubated at IIT Delhi.