Scientists tread carefully through a seemingly endless landscape of ice, sea, and meltwater in the Canada Basin of the Arctic on July 22, 2005. The blanket of ice coating Earth's northernmost seas was thin and ragged in July, setting a record low for sea ice extent for the month. Sea ice stretched across only 3.06 million square miles whereas the long-term July average is 3.9 million. Scientist note that this breakup of ice is a result of global warming. Photo made from the U.S. Coast Guard Icebreaker Healy. UPI/Jeremy Potter/NOAA |
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SEATTLE, Aug. 14 (UPI) -- The snow pack atop arctic ice sheets has been thinning for more than half a century now, researchers at the University of Washington say.
Scientists looked at the snow accumulation through the decades by compiling data from NASA's IceBridge air surveys, collected from 2009 to 2013, as well as data from buoys frozen into ice sheets by the U.S. Army Corps of Engineers. The more recent data was pooled and then compared and contrasted to historic ice flow data collected by Russian scientists from 1954 to 1991.
The numbers confirm that spring snow in many regions of the arctic is anywhere from one-third to half as thick as it was in the 1950s, when Russian scientists first started measuring.
Washington researchers also trekked out onto ice sheets to hand measure (using a high tech probe) the thickness of the snow in order to confirm the data collected by NASA's IceBridge airplane. Their work is detailed in the latest issue of the Journal of Geophysical Research: Oceans.
"Knowing exactly the error between the airborne and the ground measurements, we're able to say with confidence, yes, the snow is decreasing in the Beaufort and Chukchi seas," explained study co-author Ignatius Rigor, an oceanographer at Washington's Applied Physics Laboratory.
Rigor and his colleagues aren't exactly sure what the thinning snow means for the arctic and the climate at large. The snow blankets that rest atop the arctic's ice sheets have a thermos-like effect, shielding the ice from the arctic air. A thinner blanket may mean the ice can accumulate thicker and faster in the winter, but melt easier in the spring and summer.
Researchers say more research is needed to understand the long-term implications, but less protected could affect the regions weather as well as the ecosystem. Low-light microscopic plants that grow underneath the ice and benefit from the snow's protection for the base of the arctic's food web, and animals used the snow to build dens for shelter from the elements.
