Decline in Atlantic Niño prediction skill in the North American multi-model ensemble

The Atlantic Niño has attracted considerable attention due to its profound climatic impacts. It has been reported that the strength of Atlantic Niño has been weakening since 2000, but it is not clear whether it would lead to a change in Atlantic Niño prediction skill. Here we find a dramatic decline in Atlantic Niño prediction skill since 2000 by evaluating the predictions of the North American Multi-Model Ensemble. The prediction skill decline is mainly associated with a climatic regime shift, which leads to a weakened El Niño-Southern Oscillation (ENSO) teleconnection to the sea surface temperature anomaly dipole mode over the South Atlantic. A systematic model deficiency may amplify the prediction skill decline. This study offers insights for understanding the Atlantic Niño predictability and for improving the simulation and prediction of Atlantic Niño events. Prediction skill of the Atlantic Niño has declined over the past two decades as a result of a weakened teleconnection with El Niño/Southern Oscillation, which is amplified by a systematic model deficiency, suggest analyses of the North American multi-model ensemble simulations.