Cold winter extremes in northern continents linked to Arctic sea ice loss
Qiuhong Tang, Xuejun Zhang, Xiaohua Yang and Jennifer A Francis
Abstract
The satellite record since 1979 shows downward trends in Arctic sea ice extent in all months, which are smallest in winter and largest in September. Previous studies have linked changes in winter atmospheric circulation, anomalously cold extremes and large snowfalls in mid-latitudes to rapid decline of Arctic sea ice in the preceding autumn. Using observational analyses, we show that the winter atmospheric circulation change and cold extremes are also associated with winter sea ice reduction through an apparently distinct mechanism from those related to autumn sea ice loss. Associated with winter sea ice reduction, a high-pressure anomaly prevails over the subarctic, which in part results from fewer cyclones owing to a weakened gradient in sea surface temperature and lower baroclinicity over sparse sea ice. The results suggest that the winter atmospheric circulation at high northern latitudes associated with Arctic sea ice loss, especially in the winter, favors the occurrence of cold winter extremes at middle latitudes of the northern continents.
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1 comment:
Thanks for this link to Jennifer Francis's new collaborative paper. Helping weather forecasters, scientists, and the public understand how global "warming" can lead to consistently harsher cold spells in subarctic northern latitudes, owing to loss of autumnal and winter arctic sea ice is absolutely vital. Otherwise, people in New England see more cold, more snow and think that global warming is wrong. Rather, what we are seeing is how Arctic warming weakens the jet stream that normally prevents cold air from meandering south -- and thus what we are seeing are the early stages of how "warm" paleoclimate times smooth out latitudinal differences -- thus allowing camels to live on Ellesmere Island 3.5 million years ago. A fundamentally different northern hemisphere climate will be the result. Note: I added this new research link to the Youtube video extract I posted of Jennifer Francis teaching how Arctic sea ice loss weakens the jet stream, at "Climate Change and Extreme Weather: Jennifer Francis (2013).
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