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Arctic Decline Doubles Severe Winters In Eurasia

26.10.2014
26.10.2014 18:00 Age: 3 yrs

Declining Arctic sea ice has doubled the probability of severe winters in Europe and Asia, according to research published in Nature Geoscience.

Click to enlarge. Fig a (caption below).

Click to enlarge. Fig b (caption below)

Click to enlarge. Fig c (caption below).

Click to enlarge. Fig d (above). Caption for all figures: Observed and simulated change in winter SAT and atmospheric circulation associated with sea-ice retreat in the Barents–Kara region. a,b, Differences of composite fields between the low- and high-ice years (that is, the former minus the latter) for SAT (colour) and SLP (contours) in DJF, taken from ERA-Interim (a) and the 100-member ensembles of the LICE and HICE experiments (b). Contour interval is 0.8 hPa in a and 0.2 hPa in b, with negative contours dashed. Stippling indicates regions of significant difference exceeding 95% statistical confidence. c,d, Differences of composite fields between the low- and high-ice years (that is, the former minus the latter) for Z500 in DJF, taken from ERA-Interim (c) and the 100-member ensembles of the LICE and HICE experiments (d). Stippling indicates regions of significant difference exceeding 95% statistical confidence. Courtesy: authors and Nature Geoscience.

This new study agrees with previous work that the decline in sea ice cover in the Barents-Kara Sea area in early winter has led in recent years to unusually cold winters throughout Eurasia, including the UK, according to Colin Summerhayes, Emeritus Associate of the Scott Polar Research Institute in the UK.

Summerhayes explains that the warming of the atmosphere associated with the absence of sea ice weakens the high level winds of the polar vortex. That in turn leads to meandering of the jet stream, with the meanders becoming stuck which is what meteorologists call 'blocking'. This pull cold air south out of the Arctic, and because the system is stuck in position, the cold air supply can last quite a while.

Summerhayes points out that other factors also influence the polar vortex that controls the jet stream and so more research is needed to see how the interaction of all the controlling factors may affect the pattern of blocking in a warming world.

Abstract

Over the past decade, severe winters occurred frequently

Citation

Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades by Masato Mori, MasahiroWatanabe, Hideo Shiogama, Jun Inoue and Masahide Kimoto published in Nature Geoscience, online: 26 October 2014, DOI: 10.1038/NGEO2277

Read the abstract and get the paper here

Source

Nature press release.