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                     Massive Lake Found Under Greenland Ice

   by VOA News

   A massive lake has been found under the ice in Greenland.  The 43,500
   square kilometer body of water could have major implications for
   understanding sea level rise.
   Researchers at the [1]University of Utah say the lake, known as a
   "perennial firn aquifer," remains liquid year-round despite the
   otherwise perpetually frozen landscape.
   "Large amounts of snow fall on the surface late in the summer and
   quickly insulates the water from the subfreezing air temperatures
   above, allowing the water to persist all year long," said Rick Forster,
   lead author and professor of geography at the University of Utah.
   The Greenland Ice Sheet is vast, covering roughly the same area as the
   states of California, Nevada, Arizona, New Mexico, Colorado and Utah
   combined. The average thickness of the ice is 5,000 feet. In 2012, the
   ice sheet lost volume of 60 cubic miles - a record for melt and runoff.
   "Of the current sea level rise, the Greenland Ice Sheet is the largest
   contributor - and it is melting at record levels," said Forster. "So
   understanding the aquifer's capacity to store water from year to year
   is important because it fills a major gap in the overall equation of
   meltwater runoff and sea levels."
   Since 2010, Forster's team has measured snow accumulation Greenland and
   how it varies from year to year. The area they study covers 14 percent
   of southeast Greenland yet receives 32 percent of the entire ice
   sheet's snowfall, but there has been little data gathered.
   In 2010, the team drilled core samples in three locations on the ice
   for analysis. Team members returned in 2011 to approximately the same
   area, but at lower elevation. Of the four core samples taken then, two
   came to the surface with liquid water pouring off the drill while the
   air temperatures were minus 20 degrees centigrade. The water was found
   at about 10 meters below the surface at the first hole and at 25 meters
   in the second hole.
   "This discovery was a surprise," Forster says. "Although water
   discharge from streams in winter had been previously reported, and snow
   temperature data implied small amounts of water, no one had yet
   reported observing water in the firn that had persisted through the
   winter."
   The consequences of losing the Greenland Ice Sheet could be
   catastrophic. If all the water retained in the ice sheet melted, it is
   estimated that the global sea level would rise about 6 meters, says
   Forster.
   Although no one is predicting a total meltoff all at once, keeping an
   eye on ice formation, runoff amounts and how the water is moving is
   critical to accurately predicting sea level changes.
   Until now, calculations of the ice sheet mass changes did not include a
   year-round storage mechanism for liquid water.
   Forster says the reservoir's exact role is unknown. "It might conserve
   meltwater flow and thus help slow down the effects of climate change.
   But it may also have the opposite effect, providing lubrication to
   moving glaciers and exacerbating ice velocity and calving increasing
   the mass of ice loss to the global ocean."
   As for whether climate change caused the aquifer to form, Forster says
   that's not clear, but simulations of the Greenland Ice Sheet going back
   to the early 1970s would suggest it has been around for some time.
   The study was published online Sunday, Dec. 22, in the journal Nature
   Geoscience.
     __________________________________________________________________

   [2]http://www.voanews.com/content/massive-lake-found-under-greenland-ic
   e/1815916.html

References

   1. http://unews.utah.edu/news_releases/greenland-ice-stores-liquid-water-year-round/
   2. http://www.voanews.com/content/massive-lake-found-under-greenland-ice/1815916.html