Featured Research

from universities, journals, and other organizations

Greenland's Glaciers Pick Up Pace In Surge Toward The Sea

Date:
April 3, 2006
Source:
University of Washington
Summary:
With warming temperatures as the possible underlying cause, scientists wonder what is pushing Greenland's glaciers out to sea as much as 50 percent quicker than before. As a glacier loses large pieces of ice on its leading edge, a process called calving, openings may be created for ice to stream through more quickly, sort of like water flooding through a break in a dike or dam, suggests a glaciologist with the University of Washington.

Ian Joughin deploys a solar panel, battery and GPS receiver on an ice stream, one of the ways scientists monitor stick-slip motion of glaciers.
Credit: Image courtesy of University of Washington

With warming temperatures as the possible underlying cause, scientists wonder what is pushing Greenland's glaciers out to sea as much as 50 percent quicker than before.

As a glacier loses large pieces of ice on its leading edge, a process called calving, openings may be created for ice to stream through more quickly, sort of like water flooding through a sudden break in a dike or dam, suggests Ian Joughin, a glaciologist with the University of Washington's Applied Physics Laboratory.

"Greenland Rumbles Louder as Glaciers Accelerate" is Joughin's commentary in this week's Science on work reported by Harvard University's Goran Ekstrom and co-authors saying that glacier quakes, one way scientists can monitor glacial activity, have increased dramatically. The Ekstrom article says that seismic data from 1993 through 2005 reveals summer glacial seismicity nearly five times greater than in winter, and a rapid increase in seismicity from 2002 onwards, with 2005 producing nearly as many events as the combined total for 1993 through 1996.

The authors of that research article hypothesize that the ice is slipping on growing pockets of meltwater, like a car hydroplaning on rain-slicked streets. The meltwater drains during the summer from the surface of the glacier to the bed through glacial conduits called moulins.

Because calving of Greenland's fastest-moving glacier, Jakobshavn Isbrae, has an annual variability similar to its glacier quakes, Joughin writes that other explanations may revolve around calving.

"Large calving events alone might yield mass displacements sufficient to produce glacier quakes," he writes. "Alternatively, changes in glacier geometry after a calving event introduce a force imbalance, which may yield a slip event as new force balance is established."

Or perhaps glacier quakes are produced by stick-slip events that occur in the normal course of glacier sliding, with only hour-long periods of sticking required to build enough elastic strain to produce a detectable slip event when the ice begins to move again, he says.

Joughin, who published findings two years ago that the Jakobshavn Isbrae glacier had doubled its speed between 1997 and 2003, uses radar images from satellites to monitor the glaciers he studies.

Seismic activity has been monitored locally in Antarctica and elsewhere by placing seismometers on the glaciers. Now the Ekstrom group has determined that glacier quakes could be detected even half a world away by the existing network of seismometers that measures regular earthquakes.

"This teleseismic data provides a powerful new means for monitoring glacial activity," Joughin says.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Greenland's Glaciers Pick Up Pace In Surge Toward The Sea." ScienceDaily. ScienceDaily, 3 April 2006. <www.sciencedaily.com/releases/2006/04/060402221223.htm>.
University of Washington. (2006, April 3). Greenland's Glaciers Pick Up Pace In Surge Toward The Sea. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2006/04/060402221223.htm
University of Washington. "Greenland's Glaciers Pick Up Pace In Surge Toward The Sea." ScienceDaily. www.sciencedaily.com/releases/2006/04/060402221223.htm (accessed July 29, 2014).

Share This




More Earth & Climate News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Climate Change Could Cost Billions According To White House

Climate Change Could Cost Billions According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Jane Goodall Warns Great Apes Face Extinction

Jane Goodall Warns Great Apes Face Extinction

AFP (July 29, 2014) The world's great apes face extinction within decades, renowned chimpanzee expert Jane Goodall warned Tuesday in a call to arms to ensure man's closest relatives are not wiped out. Duration: 00:58 Video provided by AFP
Powered by NewsLook.com
Rat Infestation at Paris' Tuileries Garden

Rat Infestation at Paris' Tuileries Garden

AFP (July 29, 2014) An infestation of rats is causing concern among tourists at Paris' most famous park -- the Tuileries garden next to the Louvre Museum. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins