Challenges in Monsoon Prediction

Abstract

In this plenary lecture, I will discuss various aspects of seasonal and decadal monsoon forecasting for the Indian monsoon. In the initial years, the seasonal forecasts for the Indian summer monsoon rainfall (ISMR) are based on statistical methods using predictors representing the monsoon teleconnections. In 2017, the India Meteorological Department (IMD) introduced the statistical ensemble forecasting system, which was used by IMD for operational forecasts. With the rapid advancements in coupled modelling strategies and tools, the seasonal forecasts for monsoon rainfall are now produced using coupled ocean-atmosphere models. In 2021, IMD introduced multi-model ensemble forecasts based on different dynamical models. These models have shown more skill compared to the current statistical models. However, the current seasonal forecast skill is still far below the potential predictability. The ways in which the seasonal forecasts can be further improved will be discussed. Since the monsoon precipitation exhibits significant multi-decadal variability, attempts are being made to predict the decadal variability of the monsoon precipitation. However, recent results suggest that the decadal prediction for south Asian monsoon region is currently not very skilful.