Blog Archive

Saturday, February 5, 2011

Mark Serreze: "Could the annual decline of ice extent that we've seen actually be starting to alter weather patterns?" he asked. "It's a real example of why we've got to realize the Arctic is important."


Frigid U.S., warm Arctic — what gives?

Weird weather shows 'why we've got to realize the Arctic is important,' expert says


Image: Map of sea ice
This map by the National Snow and Ice Data Center shows the extent of Arctic sea ice in January, and how it compares to the 1979-2010 median (purple line).




msnbc.com, February 4, 2011
While much of the U.S. is seeing a wicked winter, the Arctic is going through just the opposite: January saw the least amount of sea ice for that month on record, plus the region's air temperatures are way above normal. So experts are asking themselves: are these two events intertwined?
La Nina, the naturally occurring (i.e., not manmade) ocean cycle, is certainly a factor in terms of the precipitation coming off the Gulf of Mexico that's colliding with the cold Arctic air.
But what's rare is the Arctic air moving so far south and in several rounds this winter.
It's well documented that the Arctic has been warming much faster than other parts of the world in recent years, and many experts tie that to manmade emissions of greenhouse gases that trap heat.
But the question of whether the Arctic warming translates into long-term weather changes over a wider area is "very cutting-edge stuff" and as yet unproven, Mark Serreze, director of the National Snow and Ice Data Center, recently told Reuters.
On its website, the center notes that "when sea ice has not formed during autumn and winter, heat from the ocean escapes and warms the atmosphere."
It goes on to theorize that "this may weaken the polar vortex and allow air to spill out of the Arctic and into mid-latitude regions in some years, bringing potentially cold winter weather to lower latitudes."
This phenomenon has become known as the "reverse Arctic Oscillation" — and is thought to undermine the "polar vortex," which traps cold air with a circular wind pattern.
"You get a warm Arctic and you get cold outbreaks in the middle latitudes," Serreze said.
"Could the annual decline of ice extent that we've seen actually be starting to alter weather patterns?" he asked. "It's a real example of why we've got to realize the Arctic is important."
The center, based in Boulder, Colo., tracks Arctic sea ice and this week reported that last month saw the lowest extent for any January in the satellite record since 1979.
Moreover, last December 2010 was the lowest for any December on record.
Of even greater concern is the wide extent of ice melt at the end of last summer, Serreze said.
Arctic ice coverage in September was the third lowest since the center began keeping records, a condition that caused heat to linger in the Arctic, creating a lag effect probably still evident, he said.
Temperatures have also been unusually warm — 4-11 °F above normal in January, the data center reported. "Over the eastern Canadian Arctic Archipelago, Baffin Bay/Davis Strait and Labrador Sea, temperatures were at least 11 °F higher than average," it noted.
There, much of the water remains ice-free; it is usually completely frozen over by November.
"Hudson Bay did not completely freeze up until mid-January, about a month later than normal," the data center stated. "The Labrador Sea region is still largely free of ice, except in protected bays along the coast. Normally at this time of year, ice extends several hundred kilometers from the coast all the way to northern Nova Scotia."
Schizo winter in Alaska In the U.S., Alaska has had its share of weird weather this winter.
Fairbanks residents are still recovering from November's "Icepocalypse," when rain fell on for a record 39 consecutive hours, coating the city in thick ice and closing schools and government offices.
November's rain stretched all the way to Barrow, Alaska's northernmost community, according to National Weather Service records.
"Any winter rain in that part of Alaska is highly unusual, said Chris Cox, a National Weather Service meteorologist in Fairbanks.
Since then, Alaska weather has fluctuated wildly.
December was bone chilling. Anchorage temperatures were about 6 degrees below average over the month, while in Fairbanks — where residents endured 27 days when thermometers failed to register above zero — temperatures were 12 degrees below average, according to the National Weather Service.
Balmy weather returned in early January.
In Fairbanks, "we went from 41 below to 41 above in basically just around two weeks' time," Cox said.
In Anchorage, skating rinks and ski trails melted away, and a sled-dog race was canceled because the 48-degree temperature was too hot for the dogs.
Msnbc.com's Miguel Llanos and Reuters contributed to this report.

No comments: