title: Bidecadal North Atlantic ocean circulation variability controlled by timing of volcanic eruptions.
abstract: While bidecadal climate variability has been evidenced in several North Atlantic paleoclimate records, its drivers remain poorly understood. Here we show that the subset of CMIP5 historical climate simulations that produce such bidecadal variability exhibits a robust synchronization, with a maximum in Atlantic Meridional Overturning Circulation (AMOC) 15 years after the 1963 Agung eruption. The mechanisms at play involve salinity advection from the Arctic and explain the timing of Great Salinity Anomalies observed in the 1970s and the 1990s. Simulations, as well as Greenland and Iceland paleoclimate records, indicate that coherent bidecadal cycles were excited following five Agung-like volcanic eruptions of the last millennium. Climate simulations and a conceptual model reveal that destructive interference caused by the Pinatubo 1991 eruption may have damped the observed decreasing trend of the AMOC in the 2000s. Our results imply a long-lasting climatic impact and predictability following the next Agung-like eruption.
authors.affiliation: Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), UMR CNRS 5805 EPOC-OASU-Université de Bordeaux, Allée Geoffroy Saint-Hilaire, Pessac 33615, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Swingedouw
authors.affiliation: LOCEAN/IPSL Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, 4 place Jussieu, Paris F-75005, France.
authors.forename: Pablo
authors.initials: P
authors.lastname: Ortega
authors.affiliation: 1] LOCEAN/IPSL Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, 4 place Jussieu, Paris F-75005, France [2] Climate and Environmental Physics, Physics Institute, University of Bern, Falkenplatz 16, 3012 Bern, Switzerland [3] Oeschger Centre of. Climate Change Research, University of Bern, Falkenplatz 16, Bern 3012, Switzerland.
authors.forename: Juliette
authors.initials: J
authors.lastname: Mignot
authors.affiliation: 1] LOCEAN/IPSL Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, 4 place Jussieu, Paris F-75005, France [2] NCAS-Climate, Univeristy of Reading, Reading RG6 6BB, UK.
authors.forename: Eric
authors.initials: E
authors.lastname: Guilyardi
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement (Institut Pierre Simon Laplace, CEA-CNRS-UVSQ, UMR8212), 91191 Gif-sur-Yvette, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Masson-Delmotte
authors.affiliation: School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, UK.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Butler
authors.affiliation: LOCEAN/IPSL Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, 4 place Jussieu, Paris F-75005, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Khodri
authors.affiliation: Centre National de Recherches Météorologiques-Groupe d'Etude de l'Atmosphère Météorologique/Groupe de Météorologie de Grande Echelle et Climat, Toulouse 31100, France.
authors.forename: Roland
authors.initials: R
authors.lastname: Séférian
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