Is the AMV teleconnection to the tropical Pacific robust? A multi-model large ensemble study

Abstract

Atlantic Multidecadal Variability (AMV) remotely contributes to decadal tropical Pacific climate variability. While idealised experiments with oceanic nudging show that the warm AMV phase (AMV+) drives tropical Pacific cooling, free-running climate models show that AMV+ induces tropical Pacific warming instead. It remains unclear whether this opposite-signed AMV effect is robust across different models and to the potential influence of internal variability. We examine the AMV–Pacific teleconnection in historical multi-model large ensemble simulations. We find a Niño 3.4 sea surface temperature (SST) anomaly of 0.03(±0.05) K to 0.12(±0.03) K between AMV+ and AMV− across models. The spread in magnitudes of Atlantic and Pacific SST anomalies is uncorrelated; however, we find significant inter-model relationships between AMV strength, North Atlantic surface heat flux anomalies and the tropical Walker circulation response. Our findings highlight the need for a multi-model large ensemble approach to evaluate AMV and its climate impacts.