Seasonal predictability of North Atlantic sea surface temperature under different AMV phases

Atlantic multidecadal variability (AMV) has profound climate impacts on both local and remote areas. Traditional analyses mostly concentrated on the AMV impacts on decadal-multidecadal variability. Recent studies show that AMV could also exert significant impacts on El Nino-Southern Oscillation (ENSO) and its connection with the Indian ocean dipole. However,  little attention has been paid to the AMV impacts on seasonal predictability. Based on observations and sets of ensemble hindcast products, for the first time, this study investigates the role of AMV phase on the seasonal predictability of sea surface temperature anomalies (SSTA) in North Atlantic. Our results show that the seasonal prediction skill and potential predictability of spring SSTA over the subtropical North Atlantic (STNA) region is significantly higher in AMV+ than in AMV- period. Similar contrasts between AMV phases are also obtained by the persistence skill of the observed SSTA over STNA at various lead months. Further analyses show that the differed seasonal predictability between different AMV phases are closely connected to the different upper ocean heat content, which is primarily contributed by different heat convergence driven by the Atlantic meridional overturning circulation.