Climate Dynamics

, Volume 48, Issue 7, pp 2405–2418

Tropospheric circulation during the early twentieth century Arctic warming

  • Martin Wegmann
  • Stefan Brönnimann
  • Gilbert P. Compo
Article

DOI: 10.1007/s00382-016-3212-6

Cite this article as:
Wegmann, M., Brönnimann, S. & Compo, G.P. Clim Dyn (2017) 48: 2405. doi:10.1007/s00382-016-3212-6

Abstract

The early twentieth century Arctic warming (ETCAW) between 1920 and 1940 is an exceptional feature of climate variability in the last century. Its warming rate was only recently matched by recent warming in the region. Unlike recent warming largely attributable to anthropogenic radiative forcing, atmospheric warming during the ETCAW was strongest in the mid-troposphere and is believed to be triggered by an exceptional case of natural climate variability. Nevertheless, ultimate mechanisms and causes for the ETCAW are still under discussion. Here we use state of the art multi-member global circulation models, reanalysis and reconstruction datasets to investigate the internal atmospheric dynamics of the ETCAW. We investigate the role of boreal winter mid-tropospheric heat transport and circulation in providing the energy for the large scale warming. Analyzing sensible heat flux components and regional differences, climate models are not able to reproduce the heat flux evolution found in reanalysis and reconstruction datasets. These datasets show an increase of stationary eddy heat flux and a decrease of transient eddy heat flux during the ETCAW. Moreover, tropospheric circulation analysis reveals the important role of both the Atlantic and the Pacific sectors in the convergence of southerly air masses into the Arctic during the warming event. Subsequently, it is suggested that the internal dynamics of the atmosphere played a major role in the formation in the ETCAW.

Keywords

Arctic climate Arctic warming Circulation Reanalysis Reconstructions Troposphere Climate change Heat flux 

Supplementary material

382_2016_3212_MOESM1_ESM.docx (3.3 mb)
Supplementary material 1 (DOCX 3331 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Martin Wegmann
    • 1
    • 2
  • Stefan Brönnimann
    • 1
    • 2
  • Gilbert P. Compo
    • 3
    • 4
  1. 1.Oeschger Centre for Climate Change ResearchUniversity of BernBernSwitzerland
  2. 2.Institute of GeographyUniversity of BernBernSwitzerland
  3. 3.Cooperative Institute for Research in Environmental SciencesUniversity of ColoradoBoulderUSA
  4. 4.Physical Sciences DivisionNOAA Earth System Research LaboratoryBoulderUSA

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