Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. Earth Science News .




ICE WORLD
Greenland's fastest glacier reaches record speeds
by Staff Writers
Munich, Germany (SPX) Feb 05, 2014


Iceberg from Jakobshavn Isbrae, Disko Bay. Image courtesy Ian Joughin, PSC/APL/UW.

Jakobshavn Glacier is moving ice from the Greenland ice sheet into the ocean at a speed that appears to be the fastest ever recorded. Researchers from the University of Washington and the German Space Agency (DLR) measured the dramatic speeds of the fast-flowing glacier in 2012 and 2013. The results are published today in The Cryosphere, an open access journal of the European Geosciences Union (EGU).

"We are now seeing summer speeds more than 4 times what they were in the 1990s on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland," says Ian Joughin, a researcher at the Polar Science Center, University of Washington and lead-author of the study.

In the summer of 2012 the glacier reached a record speed of more than 17 kilometres per year, or over 46 metres per day. These flow rates are unprecedented: they appear to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica, the researchers say.

They note that summer speeds are temporary, with the glacier flowing more slowly over the winter months. But they add that even the annually averaged speedup over the past couple of years is nearly 3 times what it was in the 1990s.

This speedup of Jakobshavn Isbrae means that the glacier is adding more and more ice to the ocean, contributing to sea-level rise. "We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm. With the additional speed it likely will contribute a bit more than this over the next decade," explains Joughin.

Jakobshavn Isbrae, which is widely believed to be the glacier that produced the large iceberg that sank the Titanic in 1912, drains the Greenland ice sheet into a deep ocean fjord on the coast of the island. At its calving front, where the glacier effectively ends as it breaks off into icebergs, some of the ice melts while the rest is pushed out, floating into the ocean. Both of these processes contribute about the same amount to sea-level rise from Greenland.

As the Arctic region warms, Greenland glaciers such as Jakobshavn Isbrae have been thinning and calving icebergs further and further inland. This means that, even though the glacier is flowing towards the coast and carrying more ice into the ocean, its calving front is actually retreating. In 2012 and 2013, the front retreated more than a kilometre further inland than in previous summers, the scientists write in the new The Cryosphere study.

In the case of Jakobshavn Isbrae, the thinning and retreat coincides with an increase in speed. The calving front of the glacier is now located in a deeper area of the fjord, where the underlying rock bed is about 1300 metres below sea level, which the scientists say explains the record speeds it has achieved. "As the glacier's calving front retreats into deeper regions, it loses ice - the ice in front that is holding back the flow - causing it to speed up," Joughin clarifies.

The team used satellite data to measure the speed of the glacier as part of US National Science Foundation (NSF) and NASA studies. "We used computers to compare pairs of images acquired by the German Space Agency's (DLR) TerraSAR-X satellites. As the glacier moves we can track changes between images to produce maps of the ice flow velocity," says Joughin.

The researchers believe Jakobshavn Isbrae is in an unstable state, meaning it will continue to retreat further inland in the future. By the end of this century, its calving front could retreat as far back as the head of the fjord through which the glacier flows, about 50 km upstream from where it is today.

Joughin, I., Smith, B. E., Shean, D. E., and Floricioiu, D.: Brief Communication: Further summer speedup of Jakobshavn Isbrae, The Cryosphere, 8, 209-214, doi:10.5194/tc-8-209-2014, 2014.

.


Related Links
European Geosciences Union
The Cryosphere
Beyond the Ice Age






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ICE WORLD
Greenhouse "Time Machine" Sheds Light on Corn Domestication
Washington DC (SPX) Feb 05, 2014
By simulating the environment when corn was first exploited by people and then domesticated, Smithsonian scientists discovered that corn's ancestor, a wild grass called teosinte, may have looked very different then than it does today. The fact that it looks more like corn under these conditions may help to explain how teosinte came to be selected by early farmers who turned it into one of ... read more


ICE WORLD
Fire erupts at US nuclear waste plant

Repairs may mean darker hue for Rio's iconic Christ statue

Prisoners again bolt typhoon-damaged Philippine jail

One in 4 Japan tsunami children needs psychiatric care

ICE WORLD
Oman orders NASAMS air defense system

A Proposal For The Space Debris Society

Storage system for 'big data' dramatically speeds access to information

Raytheon secures first international customer for its F-16 RACR AESA radar

ICE WORLD
Satellites Show California Water Storage at Near-Decade Low

Is there an ocean beneath our feet?

Smithsonian reports fiery-red coral species discovered in the Peruvian Pacific

Can workshops on household water use impact consumer behavior?

ICE WORLD
NASA Radar Maps the Winter Pace of Iceland's Glaciers

Arctic lakes show climate on thin ice

Greenland's fastest glacier reaches record speeds

Greenhouse "Time Machine" Sheds Light on Corn Domestication

ICE WORLD
Herbicides may not be sole cause of declining plant diversity

Local foods offer tangible economic benefits in some regions

Are invasive plants a problem in Europe? Controversial views among invasion biologists

Beneficial insects, nematodes not harmed by genetically modified, insect-resistant crops

ICE WORLD
New Indonesian volcanic eruption halts search

New quake inflicts fresh damage on Greek island

Cut off by floods, British village becomes an island

Philippine typhoon survivors brace for new storm

ICE WORLD
'Do not disappoint', Nigeria's new top brass told

Vodacom sees surge in Africa mobile data usage

Head of Algeria ruling party attacks powerful intel chief

Zambia national park mining plan draws protests

ICE WORLD
Researchers discover how brain regions work together, or alone

Experiments show human brain uses one code for space, time, distance

Neanderthal lineages excavated from modern human genomes

When populations collide




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement