Mechanisms of Decadal North Atlantic Climate Variability and Implications for the Recent Cold Anomaly

Abstract Decadal sea surface temperature (SST) fluctuations in the North Atlantic Ocean influence climate over adjacent land areas and are a major source of skill predictions. However, mechanisms underlying decadal SST variability remain to be fully understood. This study isolates driving on time scales using low-frequency component analysis, which identifies spatial temporal structure variability. Based observations, large ensemble historical simulations, preindustrial control we identify mode atmosphere–ocean with dominant scale 13–18 years. Large-scale atmospheric circulation anomalies drive both through contemporaneous air–sea heat fluxes delayed ocean changes, latter involving meridional overturning horizontal gyre circulation. The alter gradient, leading reversal initial anomaly. is consistent westward propagation baroclinic Rossby waves across subtropical Atlantic. development pattern observed recent cooling subpolar suggests that cold anomaly is, part, result