10.11.2016

What is the relationship between Arctic sea ice decline and Eurasian cold winters?

by Judith Curry We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. — McCusker et al. Published earlier this week in Nature Geoscience: Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss Kelly E. McCusker, John C. Fyfe and Michael Sigmond Abstract. Surface air temperature over central Eurasia decreased over the past twenty-five winters at a time of strongly increasing anthropogenic forcing and Arctic amplification. It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents–Kara Sea. Here we use over 600 years of atmosphere-only global climate model simulations to isolate the eect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere–ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability. In our atmosphere-only simulations, we find no evidence of Arctic sea-ice loss having impacted Eurasian surface temperature. In our atmosphere–ocean simulations, we find just one simulation with Eurasian cooling of the observed magnitude but Arctic seaice loss was not involved, either directly or indirectly. Rather, in this simulation the cooling is due to a persistent circulation pattern combining a high pressure over the Barents–Kara Sea and a downstream trough.We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. These results improve our knowledge of high-latitude climate variability and change, with implications for our understanding of impacts in high-northern-latitude systems. Full access version available [here]. JC Comment:  John Fyfe sent me this paper a few weeks ago, I think it is very interesting.  I had hoped to have more time to write some comments on this, but unfortunately no time.  So I will put the paper out there for you to discuss.
This article appeared on the Climate Etc. website at https://judithcurry.com/2016/10/11/what-is-the-relationship-between-arctic-sea-ice-decline-and-eurasian-cold-winters/
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