Evaluation of a GCM in seasonal forecasting of extreme rainfall events over continental India

In recent decades, vulnerability to disasters due to Extreme Rainfall Events (ERE) has increased manifold over continental India during the south west monsoon season. It is a very important and challenging task for the advanced forecasting of such EREs on seasonal time scales which will provide enough lead time for the disaster management, smart agricultural practice and pro-active health care for example. Researchers around the world are looking at ways to improve the skill and reliability of forecasts of EREs on a range of time scales from daily to seasonal and General Circulation Models (GCMs) are now widely used to forecast EREs on a seasonal time scale. In the present study, a variable resolution general circulation model (VRGCM) is being configured and evaluated for the seasonal prediction of the number of EREs in three different categories depending upon the threshold of daily rainfall over the continental India during the monsoon (JJA) season for 16 years (i.e. 1998–2013). The skill of model prediction is evaluated by validating the simulated ERE counts with the high resolution gridded rainfall data available from the India Meteorological Department (IMD). The spatio-temporal analysis, seasonal cycle and the Interannual variability of the of EREs over continental India using GCM simulation and IMD observations shows good agreement and the model configuration has potential skill for the simulation of EREs in seasonal prediction mode and the present results provide the application of VRGCM for seamless prediction of EREs over India. Keywords: Extreme rainfall events, General circulation model, IMD, Rain category, Seasonal predictio