(Director, IITM, Mission Director)
(Associate Mission Director: Dr. A. Suryachandra Rao)
Variability in any aspect of southwest monsoon (onset, withdrawal, and quantum of rainfall) greatly influences the agriculture yield, economy, water resources, power generation, and ecosystem. Hence the Indian summer monsoon is referred as lifeline of India. If the variations in monsoon rainfall are known well in advance, it would be possible to reduce the adverse impacts related to excess or deficient rainfall. Many droughts and floods in the past highlighted this need and prompted the India Meteorological Department to develop empirical long range prediction techniques starting with Sir Gilbert Walker’s effort in 1920s. Unfortunately, the prediction of Indian Summer Monsoon rainfall has remained a challenge over the decades and skill of empirical prediction models have not improved over the years. In addition, it is equally important to predict the extremes of monsoon climate such as droughts and floods. Empirical models systematically fail to predict the extremes. Further, the long range prediction of the seasonal mean monsoon depends on dynamics of its year-to-year variations.
In recent decades dynamical numerical models have considerably improved and most of the global coupled models have shown good prediction skill of ENSO (El Nino Southern Oscillation) SST with six months lead time. The seasonal mean rainfall hindcast skill, at one season lead time, over the central Pacific is also very good. However, not much breakthrough has taken place in improving the prediction skill of Indian summer monsoon rainfall.In recent times, several new approaches (high resolution, super parameterizations, data assimilation etc.) have shown that the variability in tropics can reasonably be resolved, thereby creating a great scope for improving the monsoon prediction.
Prediction of intraseasonal variations and of the occurrence of breaks, and in particular, their duration and intensity, is very important. Prediction of monsoon break two to three weeks in advance, assumes great importance for agricultural planning (sowing, harvesting etc.) and water management.
The forecasting of monsoon rainfall on all temporal scales starting from short range (up to 3 days), medium range 3 to 10 days and extended range beyond 10 days up to one month and seasonal scale (whole season) are crucial to the farmers for the Agricultural purpose and other planning purposes of the country. The seasonal total rainfall during the whole season is the contribution received from short, medium and extended range scales.
The success of prediction over the ENSO region indicates that there is hope dynamical models to predict the monsoon rainfall. However, there are some intrinsic problems of predicting the Indian monsoon rainfall. Hence, to improve the assimilation and forecasting system especially for the monsoon region, the Minist of Earth Sciences (MoES), Govt. of India has formulated a focused mission mode programme ‘Monsoon Mission’ on the national scale under the leadership of IITM.
IITM is playing a lead role in the Monsoon Mission for designing a weather prediction model to improve Indian Monsoon weather and climate forecasts. The Mission’s goal is to build a working partnership between Academic R&D organizations and the operational Agency to improve forecast skill. The mission will work by involving academic community from the national and international academic and research institutions of prominence in the area. A state of art dynamical prediction system for seasonal mean and extended range prediction of active-break spells will be made operational in the country. Such a system for forecast will have useful implications on policy, agricultural planning, economy, etc. To make this mission a success, the MoES has signed a Memorandum of Understanding (MoU) with the National Oceanic and Atmospheric Administration (NOAA), USA under the agreement ‘Technical Cooperation for the Study of Dynamical Seasonal Prediction of Indian Monsoon Rainfall’. The Mission will implement NCEP CFS v2.0 model and identify its strength and weaknesses in the CFS model and incorporate new physics/parameterization schemes to improve the simulations/prediction skill of the monsoon rainfall. The ultimate goal of the mission is to develop an Indian Model (based on changes made to the CFS model) which will have the capability to better simulate and predict the monsoon rainfall.
Under this program, a Monsoon Mission Directorate is set up at IITM to oversee the overall functioning of the mission. The Monsoon Directorate will be advised by a High Level National Scientific Steering Committee and an International Advisory Panel of MoES will provide guidance to the Mission Directorate and also review the progress made by the Monsoon Mission projects. Further, a Standing Mission Advisory Committee will review various research project proposals from national and international partners and recommend the proposals that have direct relevance to the Mission objectives. Each component of the Mission will be headed by an Associate Director and he/she will oversee the overall functioning of the relevant mission component and report directly to the Monsoon Mission Director. The Monsoon Mission will work to achieve the following objectives: