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Ocean Dynamics

, Volume 56, Issue 1, pp 36–50 | Cite as

On the physics of the Atlantic Multidecadal Oscillation

  • Henk A. Dijkstra
  • Lianke te Raa
  • Maurice Schmeits
  • Jeroen Gerrits
Original paper

Abstract

The Atlantic Multidecadal Oscillation (AMO) is a pronounced signal of climate variability in the North Atlantic sea-surface temperature field. In this paper, we propose an explanation of the physical processes responsible for the timescale and the spatial pattern of the AMO. Our approach involves the analysis of solutions of a hierarchy of models. In the lowest member of the model hierarchy, which is an ocean-only model for flow in an idealized basin, the variability shows up as a multidecadal oscillatory mode which is able to destabilize the mean thermohaline circulation. In the highest member of the model hierarchy, which is the Geophysical Fluid Dynamics Laboratory R30 climate model, multidecadal variability is found as a dominant statistical mode of variability. The connection between both results is established by tracing the spatial and temporal expression of the multidecadal mode through the model hierarchy while monitoring changes in specific quantities (mechanistic indicators) associated with its physics. The proposed explanation of the properties of the AMO is eventually based on the changes in the spatial patterns of variability through the model hierarchy.

Keywords

Hopf Bifurcation Geophysical Fluid Dynamics Laboratory Atlantic Multidecadal Oscillation Salinity Anomaly Atlantic Multidecadal Variability 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

This work was supported by the Netherlands Organization for Scientific Research (NWO) under a PIONIER grant to H.D. and NSF grant OCE-0425484. The authors thank Mathijs Schouten for his help with the M-SSA software and Tom Delworth (GFDL) for providing the GFDL-R30 data.

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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Henk A. Dijkstra
    • 1
  • Lianke te Raa
    • 1
  • Maurice Schmeits
    • 2
  • Jeroen Gerrits
    • 3
  1. 1.Institute for Marine and Atmospheric Research UtrechtUtrecht UniversityUtrechtThe Netherlands
  2. 2.Royal Netherlands Meteorological InstituteDe BiltThe Netherlands
  3. 3.College of Oceanic and Atmospheric SciencesOregon State UniversityCorvallisUSA

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