Contrasting the Global Connections of Internal versus Forced Atlantic Multidecadal Variability

The Atlantic Multidecadal Variability (AMV) is a prominent mode of low-frequency variability of the climate system and features basin-wide sea surface temperature (SST) variations in the North Atlantic with global connections. AMV can be either internally generated through coupled ocean-atmosphere dynamics or externally forced by anthropogenic radiative forcing. Whether the internal and the forced AMVs are associated with distinctive global climate patterns is unclear. To answer this question, we analyze large-ensemble climate model simulations and find that the internal and the forced AMVs are associated with prominent climate patterns both within and outside the Atlantic. Those distinctive AMV-related patterns directly shed light on their driving mechanisms and teleconnections from/to other ocean basins. Implications for the interpretation of the observed AMV, wherein its internal and forced components co-exist, will be discussed.