The weather system known as the "polar vortex," which hammered the United States with chilly weather last winter, may become more powerful and common for Northern Hemisphere residents as the world warms, according to a recent study.
Typically contained to the Arctic, the polar vortex can push south and bring cold blasts along -- a situation that could occur more frequently in regions of North America, Europe and Asia due to disappearing ice from Russian seas.
Sea ice swirls in ocean currents off the east coast of Greenland on Aug. 17, 2012, as seen by the MODIS instrument on board the Terra satellite. Greenland's ice sheet and outlet glaciers can also be seen at left. (Credit: Flickr/NASA/GSFC/MODIS/Terra)
Sea ice helps prevent heat from exiting the planet's oceans and entering the atmosphere. But more heat enters the atmosphere and weakens the jet stream -- the lofty body of moving air that generally keeps cold Arctic air from traveling south -- when there is less ice present, according to the report's co-author Jin-Ho Yoon of the Pacific Northwest National Laboratory. In turn, the cold air has been escaping south recently.
This phenomenon of southern-moving air occurred infrequently before 2000 but has become increasingly common, the researchers conclude in their report, published Tuesday in Nature Communications.
Analyzing historical data and computer simulations, the scientists found a link between the melting sea ice and cold snaps, according to Baek-Min Kim, the report's lead author and a scientist at the Korea Polar Research Institute (Seth Borenstein, AP/Denver Post, Sept. 2).
Reprinted from ClimateWire with permission from Environment & Energy Publishing, LLC. 202-628-6500.
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