Insight into Asymmetry in the Impact of Different Types of ENSO on the NAO

Understanding the influence of El Niño–Southern Oscillation (ENSO) on North Atlantic (NAO) is critical significance for seasonal prediction. The present study found that both Niño3.4 sea surface temperature anomaly (SSTA) intensity and east-west gradient in mid-low latitude Pacific determine linkage between ENSO NAO. Based SSTA gradient, events are classified into three types: strong intensity, weak intensity-strong (WSG), equatorial ENSOs. Note former two types usually concurrent with a zonal gradient. In contrast, often associated intensity-weak SSTAs confined Pacific. anomalous circulation patterns response to exhibit asymmetric features over Atlantic. WSG-El Niño resembles negative NAO-like pattern, yet anomalies show neutral-NAO pattern. For La Niña events, their impact NAO mainly depends cold position rather than intensity. WSG-La centered equatorial-central favor steady positive anomaly. center shifts equatorial-eastern cannot profoundly climate. physical mechanisms also investigated general model.