Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




ICE WORLD
Warm ocean drives most Antarctic ice shelf loss
by Staff Writers
Irvine CA (SPX) Jun 19, 2013


Aerial photo of front of Venable Ice Shelf, West Antarctica, an example of a small ice shelf that is a large meltwater producer. Such ice melts are far more common than previously thought and will change predictions about the thawing continent. Taken onboard the Chilean Navy P3 aircraft during the NASA/Centro de Estudios Cientificos fall 2008 campaign. NASA/JPL-Caltech/UC Irvine.

Ocean waters melting the undersides of Antarctic ice shelves, not icebergs calving into the sea, are responsible for most of the continent's ice loss, a study by UC Irvine and others has found.

The first comprehensive survey of all Antarctic ice shelves discovered that basal melt, or ice dissolving from underneath, accounted for 55 percent of shelf loss from 2003 to 2008 - a rate much higher than previously thought. Ice shelves, floating extensions of glaciers, fringe 75 percent of the vast, frozen continent.

The findings, to be published in Science, will help scientists improve projections of how Antarctica, which holds about 60 percent of the planet's freshwater locked in its massive ice sheet, will respond to a warming ocean and contribute to sea level rise.

It turns out that the tug of seawaters just above the freezing point matters more than the breaking off of bergs.

"We find that iceberg calving is not the dominant process of ice removal. In fact, ice shelves mostly melt from the bottom before they even form icebergs," said lead author Eric Rignot, a UC Irvine professor who's also a researcher with NASA's Jet Propulsion Laboratory in Pasadena. "This has profound implications for our understanding of interactions between Antarctica and climate change. It basically puts the Southern Ocean up front as the most significant control on the evolution of the polar ice sheet."

Ice shelves grow through a combination of land ice flowing to the sea and snow falling on their surfaces. The researchers combined a regional snow accumulation model and a new map of Antarctica's bedrock with ice shelf thickness, elevation and velocity data captured by Operation IceBridge - an ongoing NASA aerial survey of Greenland and the South Pole. (Rignot will host a planning session of Operation IceBridge scientists at UC Irvine on June 17 and 18.)

Ocean melting is distributed unevenly around the continent. The three giant ice shelves of Ross, Filchner and Ronne, which make up two-thirds of Antarctica's ice shelves, accounted for only 15 percent. Meanwhile, less than a dozen small ice shelves floating on relatively warm waters produced half the total meltwater during the same period.

The researchers also compared the rates at which the ice shelves are shedding ice with the speed at which the continent itself is losing mass and found that, on average, the shelves lost mass twice as fast as the Antarctic ice sheet did.

"Ice shelf melt can be compensated by ice flow from the continent," Rignot said. "But in a number of places around Antarctica, they are melting too fast, and as a consequence, glaciers and the entire continent are changing."

Other authors are Jeremie Mouginot and Bernd Scheuchl of UC Irvine and Stanley Jacobs of Columbia University. Funding was provided by NASA, the National Science Foundation, and the National Oceanic and Atmospheric Administration.

.


Related Links
University of California - Irvine
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
Warm ocean water melting Antarctic ice from bottom
Washington (AFP) June 14, 2013
Warming ocean waters are melting the Antarctic ice shelves from the bottom up, researchers said Thursday in the first comprehensive study of the thick platforms of floating ice. Scientists have long known that basal melt, the melting of ice shelves from underneath, was taking place and attributed the trend to icebergs breaking off the platforms. But the new study, to be published in Frid ... read more


ICE WORLD
Scientists use gravity, topographic data to find unmapped moon craters

Australian team maps Moon's hidden craters

LADEE Arrives at Wallops for Moon Mission

NASA's GRAIL Mission Solves Mystery of Moon's Surface Gravity

ICE WORLD
Study: Mars may have had ancient oxygen-rich atmosphere

Opportunity Recovers From Another Flash-Related Reset

ExoMars 2016 Set To Complete Construction

Mars Water-Ice Clouds Are Key to Odd Thermal Rhythm

ICE WORLD
New Zealand emerges as guinea pig for global tech firms

NASA announces eight new astronauts, half are women

Lebanese start-ups seek tech boom

China confident in space exploration

ICE WORLD
Half-Time for Shenzhou 10

China's Naughty Space Models

China's space dream crystallized with Shenzhou-10 launch

China astronauts enter space module

ICE WORLD
Strange Flames on the ISS

Europe's space truck docks with ISS

Russian cargo supply craft separates from International Space Station

Russian Space Freighter to Depart From Orbital Station

ICE WORLD
Peru launches first homemade rocket

The Centaur Upper Stage

INSAT-3D is delivered to French Guiana for Arianespace's next Ariane 5 launch

A dream launch for Shenzhou X

ICE WORLD
NASA's Hubble Uncovers Evidence of Farthest Planet Forming From its Star

Exoplanet formation surprise

Sunny Super-Earth?

Kepler Stars and Planets are Bigger than Previously Thought

ICE WORLD
Raytheon extends ballistic missile defense capability through radar modernization effort

An innovative material for the green Earth

Scientists say pearls 'ratchet' themselves to form perfect spheres

Laser survey reveals detail of 'lost' city hidden in Cambodian jungle




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