Earth Science News  





.
ICE WORLD
Study Sheds Light On How Heat Is Transported To Greenland Glaciers

Using a tiny boat and a helicopter, the research team returned to Greenland in March 2010, to do the first-ever winter survey of Sermilik Fjord at the base of Helheim Glacier. During the trip, they were able to launch probes closer to the glacier than ever before-about 2.5 miles away from the glacier's edge. (Fiamma Straneo, Woods Hole Oceanographic Institution)
by Staff Writers
Woods Hole MA (SPX) Mar 30, 2011
Warmer air is only part of the story when it comes to Greenland's rapidly melting ice sheet. New research by scientists at Woods Hole Oceanographic Institution (WHOI) highlights the role ocean circulation plays in transporting heat to glaciers.

Greenland's ice sheet has lost mass at an accelerated rate over the last decade, dumping more ice and fresh water into the ocean. Between 2001 and 2005, Helheim Glacier, a large glacier on Greenland's southeast coast, retreated 5 miles (8 kilometers) and its flow speed nearly doubled.

A research team led by WHOI physical oceanographer Fiamma Straneo discovered warm, subtropical waters deep inside Sermilik Fjord at the base of Helheim Glacier in 2009.

"We knew that these warm waters were reaching the fjords, but we did not know if they were reaching the glaciers or how the melting was occurring," says Straneo, lead author of the new study on fjord dynamics published online in the March 20 edition of the journal Nature Geoscience.

The team returned to Greenland in March 2010, to do the first-ever winter survey of the fjord. Using a tiny boat and a helicopter, Straneo and her colleague, Kjetil Vage of University of Bergen, Norway, were able to launch probes closer to the glacier than ever before-about 2.5 miles away from the glacier's edge. Coupled with data from August 2009, details began to emerge of a complicated interaction between glacier ice, freshwater runoff and warm, salty ocean waters.

"People always thought the circulation here would be simple: warm waters coming into the fjords at depth, melting the glaciers. Then the mixture of warm water and meltwater rises because it is lighter, and comes out at the top. Nice and neat," says Straneo. "But it's much more complex than that."

The fjords contain cold, fresh Arctic water on top and warm, salty waters from the Gulf Stream at the bottom. Melted waters do rise somewhat, but not all the way to the top.

"It's too dense," Straneo says. "It actually comes out at the interface where the Arctic water and warm water meet." This distinction is important, adds Straneo, because it prevents the heat contained in the deep waters from melting the upper third of the glacier. Instead, the glacier develops a floating ice tongue-a shelf of ice that extends from the main body of the glacier out onto the waters of the fjord. The shape of the ice tongue influences the stability of the glacier and how quickly it flows.

In addition, the team found that vigorous currents within the fjord driven by winds and tides also play a part in melting and flow speed. "The currents in the fjord are like waves in a bath tub," Straneo says. "This oscillation and mixing contribute to heat transport to the glaciers."

The March 2010 trip marked the first time the researchers were able to observe winter-time conditions in the fjord, which is how the system probably works nine months out of the year.

"One surprise we found was that the warm waters in the fjord are actually 1 degree Celsius warmer in winter, which by Greenland standards is a lot," Straneo says. "It raises the possibility that winter melt rates might be larger than those in the summer.

"Current climate models do not take these factors into account," she adds. "We're just beginning to understand all of the pieces. We need to know more about how the ocean changes at the glaciers edge. It's critical to improving predictions of future ice sheet variability and sea level rise."

Co-authors of the work include Ruth Curry and Claudia Cenedese of WHOI, David Sutherland of University of Washington, Gordon Hamilton of University of Maine, Leigh Stearns of University of Kansas, and Kjetil Vage of University of Bergen, Norway.




Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Woods Hole Oceanographic Institution
Beyond the Ice Age



Tempur-Pedic Mattress Comparison

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News
ICE WORLD
Large-Scale Assessment Of Arctic Ocean Show Significant Increase In Freshwater Content
Bremerhaven, Germany (SPX) Mar 29, 2011
The freshwater content of the upper Arctic Ocean has increased by about 20 percent since the 1990s. This corresponds to a rise of approx. 8,400 cubic kilometres and has the same magnitude as the volume of freshwater annually exported on average from this marine region in liquid or frozen form. This result is published by researchers of the Alfred Wegener Institute in the journal Deep-Sea R ... read more

.
Get Our Free Newsletters Via Email
  


ICE WORLD
Japan's atomic plant neighbours mull leaving homes

Insurance market Lloyd's 2010 profits tumble

Japan mulls draping fabric over reactors: report

Cost of disasters tripled in 2010: Swiss Re

ICE WORLD
UN atomic watchdog raises alarm over Japan evacuations

Cancer Risk Of Backscatter Airport Scanners Is Low

IAEA worried about radiation in Japan village

Taiwan fair to see 100 tablet launches: organisers

ICE WORLD
Police, protesters clash over China dam

First Broad-Scale Maps Of Life On The Sea-Shelf

Dolphin toll from BP oil spill far higher: study

ADB and OPEC Fund aid Sierra Leone water project

ICE WORLD
Antarctic Icebergs Play A Previously Unknown Role In Global Carbon Cycle, Climate

Study Sheds Light On How Heat Is Transported To Greenland Glaciers

Large-Scale Assessment Of Arctic Ocean Show Significant Increase In Freshwater Content

Study: 2011 arctic ice extent is down

ICE WORLD
Good wheat harvest expected in Pakistan, despite floods

Local, Diversified Food Production Needed To Curb Food Price Crisis

Ants And Termites Boost Dryland Wheat Yields

Japan urges trading partners not to overreact on food safety

ICE WORLD
Thai floods kill 15 dead, thousands stranded

Climate Modelling And The Rain

Deep-Sea Volcanoes Explode

Namibia declares state of emergency after flooding

ICE WORLD
Africa turns to cellphones for better health

A New Scramble For African Riches - Its Consumers

Sudan president heads to Qatar amid Darfur violence

Burkina Faso soldiers freed from prison after protests

ICE WORLD
Research Proves No 2 Of Us Are Alike, Even Identical Twins

Researchers Detail How Neurons Decide How To Transmit Information

Rare gene defect affects both pain, smell

A New Evolutionary History Of Primates


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement