Joined up thinking for the Irish Left
Bin Charges: From Private Circus to Public Service Tue Jun 21, 2016 12:38 | Michael Taft
Beyond Grexit & Brexit, Advocating an Irish and a British role in solving Europe... Tue Jun 21, 2016 12:18 | Tony Phillips
Hardship never lasts forever? Wed May 04, 2016 15:50 | Raymond Deane
DDCI calls on New Government to Strictly Regulate Vulture Fund Acquisitions Wed May 04, 2016 15:22 | Irish Left Review
Warning: Ultra-Low Spend Economy Ahead Wed May 04, 2016 11:59 | Michael Taft
Irish Left Review >>
Centrism extremism: how horseshoe-politics silences brutality Sat Jul 02, 2016 18:25 | yeksmesh
Of Tankies, Trots and Social Democrats Thu May 12, 2016 23:41 | Gavin Mendel-Gleason
Avatars of the Advanced-Capitalist Psyche â€“ Capitain America: Civil War Mon May 09, 2016 00:07 | Gavin Mendel-Gleason
Wailings about Left Unity Sat Feb 13, 2016 01:13 | James O'Brien
The Bern Manifesto: Why I am Voting for Bernie Sanders Wed Jan 27, 2016 23:59 | Jerome Nikolai Warren
Spirit of Contradiction >>
Life should be full of strangeness, like a rich painting
Notes for a Book on Money and the Irish State - The Marshall Aid Program 15:10 Sat Apr 02, 2016
The Financial Crisis:What Have We Learnt? 19:58 Sat Aug 29, 2015
Money in 35,000 Words or Less 21:34 Sat Aug 22, 2015
THE WRATH OF KANE: BANKING CRISES AND POLITICAL POWER 09:32 Fri Jan 30, 2015
ALWAYS THE ARTISTS: WEEK THREE OF THE BANK INQUIRY 23:11 Thu Jan 22, 2015
Dublin Opinion >>
Farewell from NWL Sun May 19, 2013 14:00 | namawinelake
Happy 70th Birthday, Michael Sun May 19, 2013 14:00 | namawinelake
Of the Week? Sat May 18, 2013 00:02 | namawinelake
Noonan denies IBRC legal fees loan approval to Paddy McKillen was in breach of E... Fri May 17, 2013 14:23 | namawinelake
Gayle Killilea Dunne asks to be added as notice party in Sean Dunne?s bankruptcy Fri May 17, 2013 12:30 | namawinelake
NAMA Wine Lake >>
Study: Arctic sea ice decline may be driving snowy winters seen in recent years
Tuesday February 28, 2012 14:43 by Judith Curry - Georgia Institute of Technology
A new study led by the Georgia Institute of Technology provides further evidence of a relationship between melting ice in the Arctic regions and widespread cold outbreaks in the Northern Hemisphere. The study's findings could be used to improve seasonal forecasting of snow and temperature anomalies across northern continents.
Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, northwestern and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.
"Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation," said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech. "The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents."
These maps show the differences in snow cover relative to the long-term average for the winters of (left) 2009-2010 and (right) 2010-2011. During these two winters, the Northern Hemisphere measured its second and third largest snow cover levels on record.
The study was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences. The research was supported by NASA and the National Science Foundation.
In this study, scientists from Georgia Tech, the Chinese Academy of Sciences and Columbia University expanded on previous research by combining observational data and model simulations to explore the link between unusually large snowfall amounts in the Northern Hemisphere in recent winters and diminishing Arctic sea ice.
The researchers analyzed observational data collected between 1979 and 2010 and found that a decrease in autumn Arctic sea ice of 1 million square kilometers -- the size of the surface area of Egypt -- corresponded to significantly above-normal winter snow cover in large parts of the northern United States, northwestern and central Europe, and northern and central China.
The analysis revealed two major factors that could be contributing to the unusually large snowfall in recent winters -- changes in atmospheric circulation and changes in atmospheric water vapor content -- which are both linked to diminishing Arctic sea ice. Strong warming in the Arctic through the late summer and autumn appears to be enhancing the melting of sea ice.
"We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere," explained Jiping Liu, a senior research scientist in the School of Earth and Atmospheric Sciences at Georgia Tech. "These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States."
Diminishing Arctic sea ice can cause changes in atmospheric circulation that lead to a circulation pattern that is different than the "negative phase" of the Arctic Oscillation.
In addition to analyzing observational data, the researchers also assessed the impact of the diminishing Arctic sea ice on atmospheric circulation by comparing the results of model simulations run with different sea ice distribution. They ran one experiment that assumed seasonally varying Arctic sea ice and utilized sea ice concentration data collected between 1979 and 2010. Another simulation incorporated prescribed sea ice loss in autumn and winter based on satellite-derived Arctic sea ice concentrations.
The simulations showed that diminishing Arctic sea ice induced a significant surface warming in the Arctic Ocean and Greenland/northeastern Canada, and cooling over northern North America, Europe, Siberia and eastern Asia. The models also showed above-normal winter snowfall in large parts of the northern United States, central Europe, and northern and central China.
The consistent relationships seen in the model simulations and observational data illustrate that the rapid loss of sea ice in summer and delayed recovery of sea ice in autumn modulates snow cover, winter temperature and the frequency of cold air outbreaks in northern mid-latitudes.
Huijun Wang and Mirong Song of the Chinese Academy of Sciences Institute of Atmospheric Physics and Radley Horton from the Columbia University Center for Climate Systems Research also contributed to this work.
Impact of declining Arctic sea ice on winter snowfall.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1114910109/-/DCSupplemental.
These maps show the differences in Arctic sea ice concentration relative to the long-term average for the winters of (A) 2007-2008, (B) 2008-2009, (C) 2010-2011 and (D) 2010-2011. The lowest levels of Arctic sea ice have been measured between 2007 and 201
This map shows the percent change in winter blockings relative to the long-term average. Blocking patterns favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and M