Climate Dynamics

, Volume 45, Issue 1–2, pp 539–556

Contrasting interannual and multidecadal NAO variability

  • T. Woollings
  • C. Franzke
  • D. L. R. Hodson
  • B. Dong
  • E. A. Barnes
  • C. C. Raible
  • J. G. Pinto
Article

DOI: 10.1007/s00382-014-2237-y

Cite this article as:
Woollings, T., Franzke, C., Hodson, D.L.R. et al. Clim Dyn (2015) 45: 539. doi:10.1007/s00382-014-2237-y

Abstract

Decadal and longer timescale variability in the winter North Atlantic Oscillation (NAO) has considerable impact on regional climate, yet it remains unclear what fraction of this variability is potentially predictable. This study takes a new approach to this question by demonstrating clear physical differences between NAO variability on interannual-decadal (<30 year) and multidecadal (>30 year) timescales. It is shown that on the shorter timescale the NAO is dominated by variations in the latitude of the North Atlantic jet and storm track, whereas on the longer timescale it represents changes in their strength instead. NAO variability on the two timescales is associated with different dynamical behaviour in terms of eddy-mean flow interaction, Rossby wave breaking and blocking. The two timescales also exhibit different regional impacts on temperature and precipitation and different relationships to sea surface temperatures. These results are derived from linear regression analysis of the Twentieth Century and NCEP-NCAR reanalyses and of a high-resolution HiGEM General Circulation Model control simulation, with additional analysis of a long sea level pressure reconstruction. Evidence is presented for an influence of the ocean circulation on the longer timescale variability of the NAO, which is particularly clear in the model data. As well as providing new evidence of potential predictability, these findings are shown to have implications for the reconstruction and interpretation of long climate records.

Keywords

North Atlantic Oscillation Jet variability Atmosphere–ocean interaction Climate reconstructions 

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • T. Woollings
    • 1
  • C. Franzke
    • 2
  • D. L. R. Hodson
    • 3
  • B. Dong
    • 3
  • E. A. Barnes
    • 4
  • C. C. Raible
    • 5
  • J. G. Pinto
    • 6
    • 7
  1. 1.Department of PhysicsAtmospheric, Oceanic and Planetary PhysicsOxfordUK
  2. 2.Meteorological Institute and Center for Earth System Research and SustainabilityUniversität HamburgHamburgGermany
  3. 3.NCAS-Climate and Department of MeteorologyUniversity of ReadingReadingUK
  4. 4.Department of Atmospheric ScienceColorado State UniversityFort CollinsUSA
  5. 5.Climate and Environmental Physics and Oeschger Centre for Climate Change ResearchUniversity of BernBernSwitzerland
  6. 6.Department of MeteorologyUniversity of ReadingReadingUK
  7. 7.Institute for Geophysics and MeteorologyUniversity of CologneCologneGermany

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