INCREASE and 6th ARN - Convectively Coupled Equatorial Waves Triggering Torrential Rainfall Events
Channel: Reyhan Respati
Date: 2021-09-03

This study examines the influence of convectively coupled equatorial waves (CCEWs) and their characteristics on torrential rainfall events over Sumatra, Indonesia on a sub-monthly timescale. The analysis of the ERA-Interim reanalysis data and the gridded Asian Precipitation-Highly Resolved Observational Data Integration Toward Evaluation of Water Resources (APHRODITE) product from 1980 to 2007 showed that Kelvin waves have a major role in the formation of the extreme rainfall event, compared to other waves such as equatorial Rossby (ER), mixed Rossby-gravity (MRG), and eastward inertio gravity (EIG) waves. In particular, it is found that the Kelvin waves contribute up to +100% (-70%) change of extreme rainfall probability during their wet (dry) phase, followed by ER waves that contribute up to +80% (-50%) probability change during their wet (dry) phase. The MRG and EIG waves have much less impact compared to the other waves. An examination of the characteristics of CCEWs reveals that the extreme rainfall modulation is found to be consistent with the distribution of the center of active (suppressed) convection and convergence (divergence) induced by the waves over Sumatra, Indonesia.