title: Evidence for external forcing of the Atlantic Multidecadal Oscillation since termination of the Little Ice Age.
abstract: The Atlantic Multidecadal Oscillation (AMO) represents a significant driver of Northern Hemisphere climate, but the forcing mechanisms pacing the AMO remain poorly understood. Here we use the available proxy records to investigate the influence of solar and volcanic forcing on the AMO over the last ~450 years. The evidence suggests that external forcing played a dominant role in pacing the AMO after termination of the Little Ice Age (LIA; ca. 1400-1800), with an instantaneous impact on mid-latitude sea-surface temperatures that spread across the North Atlantic over the ensuing ~5 years. In contrast, the role of external forcing was more ambiguous during the LIA. Our study further suggests that the Atlantic Meridional Overturning Circulation is important for linking external forcing with North Atlantic sea-surface temperatures, a conjecture that reconciles two opposing theories concerning the origin of the AMO.
authors.affiliation: Centre for Past Climate Studies, Department of Geoscience, Aarhus University, Høegh-Guldsbergs Gade 2, Aarhus C DK-8000, Denmark.
authors.forename: Mads Faurschou
authors.initials: MF
authors.lastname: Knudsen
authors.affiliation: Centre for Past Climate Studies, Department of Geoscience, Aarhus University, Høegh-Guldsbergs Gade 2, Aarhus C DK-8000, Denmark.
authors.forename: Bo Holm
authors.initials: BH
authors.lastname: Jacobsen
authors.affiliation: Centre for Past Climate Studies, Department of Geoscience, Aarhus University, Høegh-Guldsbergs Gade 2, Aarhus C DK-8000, Denmark.
authors.forename: Marit-Solveig
authors.initials: MS
authors.lastname: Seidenkrantz
authors.affiliation: Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus C DK-8000, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Olsen