A model for super El Niños.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29955048.
- Also identified by DOI 10.1038/s41467-018-04803-7 and PMC identifier 6023905.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Super El Niños, the strongest and most powerful of El Niños, impact economies, societies, and ecosystems disproportionately. Despite their importance, we do not fully understand how super El Niños develop their intensity and unique characteristics. Here, combining observational analyses with simple numerical simulations, we suggest that eastern Pacific intensified super El Niños result from the interaction of an El Niño and a positive Indian Ocean Dipole. Further, we identify a self-limiting behavior inherent to El Niño Southern Oscillation (ENSO) dynamics. This behavior-a consequence of the atmospheric Kelvin wave response that develops to the east of ENSO's convective anomalies-dampens sea surface temperature (SST) variations in the eastern Pacific, thereby preventing super El Niños from developing through tropical Pacific dynamics alone. Our model explains the features of the large 1972, 1982, and 1997 El Niños; the large SST anomalies during the 2015 El Niño, however, were likely enhanced by strong decadal variability.