Climate Dynamics

, Volume 42, Issue 1–2, pp 381–399

Different flavors of the Atlantic Multidecadal Variability

  • Davide Zanchettin
  • Oliver Bothe
  • Wolfgang Müller
  • Jürgen Bader
  • Johann H. Jungclaus
Article

DOI: 10.1007/s00382-013-1669-0

Cite this article as:
Zanchettin, D., Bothe, O., Müller, W. et al. Clim Dyn (2014) 42: 381. doi:10.1007/s00382-013-1669-0

Abstract

We investigate how differently-constructed indices for North Atlantic sea-surface temperatures (NASSTs) describe the “Atlantic Multidecadal Variability” (AMV) in a suite of unperturbed as well as externally-forced millennial (pre-industrial period) climate simulations. The simulations stem from an ensemble of Earth system models differing in both resolution and complexity. Different criteria exist to construct AMV indices capturing different aspects of the phenomenon. Although all representations of the AMV maintain strong multidecadal variability, they depict different characteristics of simulated low-frequency NASST variability, evolve differently in time and relate to different hemispheric teleconnections. Due to such multifaceted signatures in the ocean-surface as well as in the atmosphere, reconstructions of past AMV may not univocally reproduce multidecadal NASST variability. AMV features under simulated externally-forced pre-industrial climate conditions are not unambiguously distinguishable, within a linear framework, from AMV features in corresponding unperturbed simulations. This prevents a robust diagnosis of the simulated pre-industrial AMV as a predominantly internal rather than externally-forced phenomenon. We conclude that a multi-perspective assessment of multidecadal NASSTs variability is necessary for understanding the origin of the AMV, its physics and its climatic implications.

Keywords

Atlantic Multidecadal Variability Sea-surface temperatures Earth system model Teleconnections Natural climate variability Externally-forced climate variability Climate of the last millennium 

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Davide Zanchettin
    • 1
  • Oliver Bothe
    • 1
    • 2
  • Wolfgang Müller
    • 1
  • Jürgen Bader
    • 1
    • 3
  • Johann H. Jungclaus
    • 1
  1. 1.Max Planck Institute for MeteorologyHamburgGermany
  2. 2.University of HamburgHamburgGermany
  3. 3.Bjerknes Centre for Climate ResearchUni ResearchBergenNorway

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