Friday, September 6, 2013

New paper finds 2009-2010 winter was colder than 1783-1784 in France

A paper in open review for Climate of the Past finds no significant difference between the atmospheric variables of sea-level pressure, surface temperature and wind speed between the winters of 1783-1784 [during the Little Ice Age] and 2009-2010 in Europe, and finds the 2009-2010 winter in France was colder than 1783-1784, in spite of a large volcanic eruption that occurred in 1783.

Excerpt: 
"The results on temperature reconstructions are coherent with historical and proxy records in Europe, especially during the Laki eruption period. D’Arrigo et al. (2011) suggested that the winter conditions in 1783/1784 resembled those of the 2009/2010 winter. Our analysis confirms this inference, although the 1783/1784 winter was not as cold as 2009/2010, at least in France."
Clim. Past Discuss., 9, 5157-5182, 2013
www.clim-past-discuss.net/9/5157/2013/
doi:10.5194/cpd-9-5157-2013

Ensemble meteorological reconstruction using circulation analogues of 1781–1785
P. Yiou1, M. Boichu2, R. Vautard1, M. Vrac1, S. Jourdain3, E. Garnier4, F. Fluteau5, and L. Menut2
1Laboratoire des Sciences du Climat et de l'Environnement, UMR8212 CEA-CNRS-UVSQ & IPSL, CE Saclay l'Orme des Merisiers, 91191 Gif-sur-Yvette, France
2Laboratoire de Météorologie Dynamique, UMR8539 X-ENS-UPMC & IPSL, Ecole Polytechnique, 91128 Palaiseau, France
3DClim, Météo France, 42 Avenue G. Coriolis, 31057 Toulouse, France
4Centre de Recherche d'Histoire Quantitative, UMR6583 Université de Caen–CNRS, 14032 Caen, France
5Institut de Physique du Globe de Paris, 1 rue Jussieu, 75238 Paris, France

Abstract. This paper uses a method of atmospheric flow analogues to reconstruct an ensemble of atmospheric variables (namely sea-level pressure, surface temperature and wind speed) between 1781 and 1785. The properties of this ensemble are investigated and tested against observations of temperature. The goal of the paper is to assess whether the atmospheric circulation during the Laki volcanic eruption (in 1783) and the subsequent winter were similar to the conditions that prevailed in the winter 2009/2010 and during spring 2010. We find that the three months following the Laki eruption in June 1783 barely have analogues in 2010. The cold winter of 1783/1784 yields circulation analogues in 2009/2010. Our analysis suggests that it is unlikely that the Laki eruption was responsible for the cold winter of 1783/1784, of the relatively short memory of the atmospheric circulation.

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