The Role of Convectively Coupled Equatorial Waves on the Intensity of Extreme Precipitation Events Over the West Coast of India

This study attempts to understand how convectively coupled equatorial waves (CCEWs) can modulate extreme rainfall events along the west coast of India during different seasons. The waves are filtered from Outgoing Longwave Radiation (OLR), and their impact on extreme precipitation events is explored. The results show that CCEWs significantly amplify rainfall extremes over the west coast, with Rossby waves having the highest impact, followed by Mixed Rossby-Gravity (MRG) and Kelvin waves. The amplification in rainfall is largely driven by wave-induced enhancement in moisture convergence and the formation of large deep convective cloud systems. The CCEWs are also observed increasing likelihood of extreme events, with Rossby and MRG waves being the main contributors. These results advance our understanding of processes that can trigger extreme rainfall along the west coast and emphasise the potential to improve their forecasts by using the filtered equatorial wave activity.