Impacts of Atlantic multidecadal variability on the tropical Pacific: a multi-model study

Atlantic multidecadal variability (AMV) has been linked to the observed slowdown of global warming over 1998-2012 through its impact on the tropical Pacific. Given the global importance of tropical Pacific variability, better understanding this Atlantic-Pacific teleconnection is key for improving climate predictions, but the robustness and strength of this link are uncertain. Analyzing a multi-model set of sensitivity experiments, we find that models differ by a factor of 10 in simulating the amplitude of the Equatorial Pacific cooling response to observed AMV warming. The inter-model spread is mainly driven by different amounts of moist static energy injection from the tropical Atlantic surface into the upper troposphere. We reduce this inter-model uncertainty by analytically correcting models for their mean precipitation biases and we quantify that, following an observed 0.26 degrees C AMV warming, the equatorial Pacific cools by 0.11 degrees C with an inter-model standard deviation of 0.03 degrees C.

Automated summary

Analyzing sensitivity experiments across multiple models revealed a significant variation in simulating the impact of Atlantic multidecadal variability (AMV) on the tropical Pacific, mainly driven by differences in moist static energy injection. Correcting models for mean precipitation biases reduced inter-model uncertainty, allowing for a more precise quantification of the cooling effect on the equatorial Pacific following AMV warming.