Atlantic Nino/Nina Prediction Skills in NMME Models

The Atlantic Nino/Nina, one of the dominant interannual variability in the equatorial Atlantic, exerts prominent influence on the Earth's climate, but its prediction skill shown previously was unsatisfactory and limited to two to three months. By diagnosing the recently released North American Multimodel Ensemble (NMME) models, we find that the Atlantic Nino/Nina prediction skills are improved, with the multi-model ensemble (MME) reaching five months. The prediction skills are season-dependent. Specifically, they show a marked dip in boreal spring, suggesting that the Atlantic Nino/Nina prediction suffers a spring predictability barrier like ENSO. The prediction skill is higher for Atlantic Nina than for Atlantic Nino, and better in the developing phase than in the decaying phase. The amplitude bias of the Atlantic Nino/Nina is primarily attributed to the amplitude bias in the annual cycle of the equatorial sea surface temperature (SST). The anomaly correlation coefficient scores of the Atlantic Nino/Nina, to a large extent, depend on the prediction skill of the Nino3.4 index in the preceding boreal winter, implying that the precedent ENSO may greatly affect the development of Atlantic Nino/Nina in the following boreal summer.

Automated summary

The prediction skill of Atlantic Nino/Nina has been improved, with the multi-model ensemble reaching five months, but it is season-dependent, showing a marked decrease in spring prediction ability.