Increased Predictability of Extreme El Niño From Decadal Interbasin Interaction

Abstract

Abstract Predicting extreme El Niño–Southern Oscillation (ENSO) events remains a formidable task. Utilizing eigen microstates (EMs) of complex systems, we elucidate the interplay of two key sea surface temperature (SST) anomaly modes, the newly identified Atlantic‐Western Pacific Multidecadal mode (AM‐WPM) and discovered Pacific Meridional Mode (PMM). Our findings demonstrate that a cold AM‐WPM phase coupled with a positive PMM phase markedly elevates the probability of extreme El Niño events; AM‐WPM's decadal variability serves as a key modulator of extreme El Niño events' frequency. Our empirical model, capitalizing on these modes, achieves robust forecasts with a 6–8 months lead time and boasts a 0.73 correlation with the observed ENSO index in hindcasts. Notably, the model precisely forecasts the intensity of four extreme El Niño episodes: 1982/1983, 1987/1988, 1997/1998, and 2015/2016. Our findings offer promising avenues for refining ENSO predictive frameworks and deepen our understanding of the key climatic drivers.