A Well-Verified, Multiproxy Reconstruction of the Winter North Atlantic Oscillation Index since A.D. 1400

Fig. 3 Multi-proxy NAO reconstruction A Well-Verified, Multiproxy Reconstruction of the Winter North Atlantic Oscillation Index since A.D. 1400
Journal of Climate, v.15, pp. 1754-1764, 2002.

Edward R. Cook and Rosanne D. D'Arrigo1
Michael E. Mann2

1 Lamont-Doherty Earth Observatory, Palisades, New York
2 Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia

ABSTRACT:
A new, well-verified, multiproxy reconstruction of the winter North Atlantic Oscillation (NAO) index is described that can be used to examine the variability of the NAO prior to twentieth century greenhouse forcing. It covers the period A.D. 14001979 and successfully verifies against independent estimates of the winter NAO index from European instrumental and noninstrumental data as far back as 1500. The best validation occurs at interannual timescales and the weakest at multidecadal periods. This result is a significant improvement over previous proxy-based estimates, which often failed to verify prior to 1850, and is related to the use of an extended reconstruction model calibration period that reduced an apparent bias in selected proxies associated with the impact of anomalous twentieth century winter NAO variability on climate teleconnections over North Atlantic sector land areas. Although twentieth century NAO variability is somewhat unusual, comparable periods of persistent positive-phase NAO are reconstructed to have occurred in the past, especially before 1650.

DATA:
Download the NAO reconstruction from this study from the WDC Paleo Archive

Other NAO reconstructions archived at WDC Paleo and discussed by Cook et al. 2002:

Reconstructed North Atlantic Oscillation Index, 280 Years, Cook et al. 1998.
Reconstructed North Atlantic Oscillation Index, 550 Years, Glueck and Stockton 2001.
Reconstructed North Atlantic Oscillation Index, 500 Years, Luterbacher et al. 2002.
Instrumental North Atlantic Oscillation Index, 180 Years, Jones et al. 1997.

The research is supported by the Cooperative Institute for Arctic Research through a partnership between NOAA and the University of Alaska.

To read or view the full study, please visit the Allen Press website.
It was published in Journal of Climate v.15, pp. 1754-1764, 2002.


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11 September 2002