Research Projects

Atmospheric rivers (ARs) are identified as narrow plumes of intense horizontal moisture transport in the lower troposphere. ARs are transient in nature, appear globally, and are responsible for more than 90% of the total poleward moisture flux at any instant. Due to their intense water vapor transport, they are shown to have significant socio-economic impacts, especially over orographically active regions, where the forced saturated ascent often results in heavy rains and snowfall. Over several regions around the globe, ARs are recognized as essential sources of regional water supply, while also condemned as causes of catastrophic winds and flooding. Recent research has shown that some major floods in India, such as the 2018 August flood in Kerela and the 2013 June flood in Uttarakhand, were associated with ARs. Some recent studies underscore the importance of ARs for the hydrology of the Himalayas. It is thus critical for us to be able to forecast ARs over the Himalayas well in advance. Several efforts have been made around the globe for forecasting ARs. For example, over the west coast of the United States, multi-year efforts are made for skillful AR forecasting through scientific advancement, numerical modeling, and field campaigns using real-time observations made by aircrafts specifically hired for ARs. Recent works that have highlighted the major contribution of ARs to the hydroclimatology of the Himalayan basins call for concerted efforts for advancing AR research on scientific and socio-economic fronts. In this proposal, we aim to: 1. Evaluate the skill of numerical weather prediction models for short-term (~ 7 days) forecasting of ARs. 2. Develop models for sub-seasonal (~15) forecasting of ARs. 3. Through oceanic and atmospheric interactions, identify the sources of predictability of ARs for seasonal-scale forecasting. 4. Based on objective 3, develop statistical models to forecast AR at a seasonal scale. We envision the following direct scientific and socio-economic benefits of the proposed project: 1. Improve early warning systems for floods, GLOFs, and other topography-dependent hazards. 2. Longer-term forecasts will help in water resources management and flood risk assessment. 3. The proposed project will help in improving the understanding of atmospheric dynamics relevant to Himalayan hydrology. 4. Forecasting of ARs will also help in predicting snow and glacier dynamics in the mountain ranges of the Himalayas. 5. We believe the proposed project will help in improving the models used for sub-seasonal and seasonal forecasting in India.