Efforts on Seasonal Forecasts under the Monsoon Mission

The Indian summer monsoon rainfall (ISMR) is the lifeline of the Indian agriculture-based economy. Anomalies and extreme events in monsoon impact the economy dearly in terms of agriculture, water management, life and property. Hence, prediction of ISMR is very important for India, especially for planning strategies for management of agricultural production and water resources, and disaster (like flood, drought, etc.) management.

Monsoon Prediction started in 1882 by Sir Blanford based on empirical relations since then the ISMR prediction remained a challenge over centuries.Historically, statistical models have been used for operational long range forecasts for the Indian summer monsoon rainfall. However, over the years, no appreciable improvement in prediction skill was noted in operational forecasts in spite of better understanding of monsoon variability and its tele-connections. Moreover, statistical models have constraints in predicting monsoon rainfall in higher spatial and temporal resolutions.

Considering the important role played by the ISMR on Indian economy, Government of India has launched a Mission mode project "Monsoon Mission" to improve the dynamical prediction of Monsson on all different time scales. For this purpose Climate Forecast System (CFS) coupled model is selected as base model to improve the skill of seasonal and extended range prediction of Monsoon rainfall. Several model biases have been identified and attempts have been made to reduce them and this presentation provides details on how the model biases have reduced and resulted in improving the monsoon prediction.