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

Abstract

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 °C AMV warming, the equatorial Pacific cools by 0.11 °C with an inter-model standard deviation of 0.03 °C.

Early warning signal for a tipping point suggested by a millennial Atlantic Multidecadal Variability reconstruction

“…1b–k ), though with a more scattered and seasonally dependent pattern. These fingerprints are in agreement with modeling studies 9 , 42 that highlight the widespread and seasonally varying teleconnection patterns of the AMV, including the remote impact over Asia (Fig. 1b–k ).…”

Inter‐Model Spread of North Tropical Atlantic Trans‐Basin Effect Substantially Biases Tropical Pacific Sea Surface Temperature Multiyear Prediction

“…Our preliminary analysis shows that the strength of NTA and TP SST variability play a role (Figure S6 in Supporting Information S1). Previous studies highlighted the model biases of mean SST and atmospheric response influcening simulated Atlantic trans-basin effect on Pacific variability (Chikamoto et al, 2020;McGregor et al, 2018;Ruprich-Robert et al, 2021). Further works are needed to address this important issue.…”

“…Chikamoto et al (2020) found a large inter-model spread of the TP trade wind response to Atlantic interannual forcing. Besides interannual variability, other studies revealed that the modeled AMV-to-IPV teleconnection is strongly influenced by mean biases of SST and precipitation (C. Li et al, 2020;McGregor et al, 2018;Ruprich-Robert et al, 2021). Yang et al (2021) reported that the AMV significantly contributes to the optimal precursor of the IPV in observations but not in models.…”

Observed Zonal Variations of the Relationship between ITCZ Position and Meridional Temperature Contrast

“…This suggests that the convection over the Western Pacific is highly linked to the Atlantic Meridional Overturning Circulation (AMOC). The link between AMOC and global precipitation was discussed extensively in a paleoclimate context, e.g., [27], and several studies, e.g., [44,45], showed the link between AMO and Pacific climate, suggesting that recent cooling in the Eastern Pacific may have been caused by abnormal warming in the North Atlantic. Our results differ from previous research because they suggest that the Western Pacific ITCZ moves southward during the warm phase of AMO.…”