Earth Day, April 22, 2008

EurekAlert.org--Researchers from the Woods Hole Oceanographic Institution (WHOI) and the University of Washington (UW) have for the first time documented the sudden and complete drainage of a lake of meltwater from the top of the Greenland ice sheet to its base.

From those observations, scientists have uncovered a plumbing system for the ice sheet, where meltwater can penetrate thick, cold ice and accelerate some of the large-scale summer movements of the ice sheet.

According to research by glaciologists Sarah Das of WHOI and Ian Joughin of UW, the lubricating effect of the meltwater can accelerate ice flow 50- to 100 percent in some of the broad, slow-moving areas of the ice sheet.

photo caption:
WHOI glaciologist Sarah Das stands in front of a block of ice that was raised up 6 meters by the sudden drainage of a meltwater lake in Greenland.  (left)

Link to full EurekAlert Press Release
"Lakes of Meltwater Can Crack Greenland’s Ice and Contribute to Faster Ice Sheet"
Woods Hole Oceanographic Institution

According to the related study, Fracture Propagation to the Base of the Greenland Ice Sheet During Supraglacial Lake Drainage, published in Science Express Reports online April 17, "the average drainage rate...during this rapid-drainage phase exceeded the average flow rate over Niagara Falls" (page 1).

Photos of melt streams were released at EurekAlert.org from a related article published in Science April 18, "Seasonal Speedup Along the Western Flank of the Greenland Ice Sheet," by Dr. Ian Joughin, Sarah Das, and colleagues. 

Both articles are available at Science Express Reports.

Ian Joughin

In snowpit at Siple Dome, Antarctica
courtesy: Ian Joughin

Related Images
"Seasonal Speedup Along The Western Flank of The Greenland Ice Sheet"

Seasonal Speedup Along the Western Flank of the Greenland Ice Sheet
Dr. Ian Joughin and Colleagues, Science, April 18, 2008

Abstracts and articles available at Science Express Reports - Sciencemag.org
 

"Antarctic Ice Loss Speeds Up, Nearly Matches Greenland Loss"

Antarctic ice loss between 1996 and 2006, overlaid on a Moderate Resolution Imaging Spectroradiometer (MODIS) mosaic image of Antarctica. The colors indicate the speed of the ice loss.
Purple/red is fast. Green is slow.
Image and source credit: NASA

January 23, 2008

PASADENA, Calif. – Ice loss in Antarctica increased by 75 percent in the last 10 years due to a speed-up in the flow of its glaciers and is now nearly as great as that observed in Greenland, according to a new, comprehensive study by NASA and university scientists. ...

Full article from NASA Jet Propulsion Laboratory

Live From the North Pole - New Web Cam
courtesy
National Oceanic and Atmospheric Administration

What do you think?

UPfirst
Question of the Week!
Click on question mark button
to read and post comments