Interaction Between the Interdecadal Pacific Oscillation and Atlantic Multidecadal Variability Lowers Their Contemporaneous Correlation

Abstract The Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Variability (AMV) substantially affect global climate system. Model studies suggested a fast interaction between the IPO and AMV through atmospheric teleconnections, but observations exhibit a weak IPO–AMV contemporaneous correlation. To address this paradox, we apply linear inverse model (LIM) in observations to decode the interaction. We reveal that a cancel effect of the interaction lowers the observed IPO–AMV contemporaneous correlation. When only retaining the one‐way modulation (the IPO forces the AMV or the reversed one) in the observational LIM, their correlation peaks nearly simultaneously, consistent with the fast IPO–AMV interaction in model experiments. We further demonstrate that the fast interaction is associated with both tropical and extratropical processes. Our study reconciles the discrepancy between observations and models on the IPO–AMV interaction.