Understanding MJO Teleconnections to the Southern Hemisphere Extratropics During El Niño, La Niña, and Neutral Years

Abstract

The Madden-Julian Oscillation (MJO) and the El Niño-Southern Oscillation (ENSO) are the two major tropical climate modes important for weather and climate predictability and teleconnections on sub-seasonal to seasonal timescales. Although the modulation of MJO teleconnections by ENSO has been extensively studied for the Northern Hemisphere, there are limited studies for the Southern Hemisphere. We investigate the impact of ENSO on MJO teleconnections during the four major seasons. We find that especially during the austral summer season, El Niño tends to significantly change the MJO teleconnections for the early MJO phases (8/1 and 2/3), while La Niña modifies them for the late MJO phases (4/5 and 6/7). The combined ENSO-MJO teleconnection composites show a higher contribution from the ENSO component to the teleconnection patterns during austral summer, with this effect being particularly pronounced during La Niña years.