Asymmetry of inter-El Niño and -La Niña diversity

Over the North Pacific, there is a distinctive asymmetry of inter-El Niño and -La Niña diversity in atmospheric teleconnection patterns, indicating a strong diversity during La Niña events. Recent studies suggested that the typical patterns of the extratopical teleconnections associated with El Niño-Southern Oscillation (ENSO) are predominantly explained by the relative roles of the equatorial central Pacific (CP) and western North Pacific (WNP) precipitation anomalies. We find that the diversity of WNP precipitation anomalies is greater during La Niña events than during El Niño events. It also implies that the diversity of WNP precipitation anomalies during La Niña events is responsible for the diversity in the extratropical teleconnection. Since the relationship of anomalous sea surface temperature (SST) to precipitation is quite sensitive for SST in the range of 27-28°C, the WNP precipitation differences located over the warm pool among La Niña events lead to considerable teleconnection changes. In addition, we find here that the CMIP5 models well simulate the overall diversity in the tropical precipitation and extratropical teleconnection patterns during La Niña events, but it fails to reproduce a detailed pattern difference of atmospheric teleconnection in inter-La Niña events.