Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Antarctic Glaciers Surge When Ice Shelves Collapse


Antarctic glaciers that had been blocked behind the Larsen B ice shelf have been flowing more rapidly into the Weddell Sea, following the break-up of that shelf. Studies based on imagery from two satellites reached similar conclusions, which will be published September 22 in the journal Geophysical Research Letters.

Researchers from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, and NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, said the findings prove that ice shelves act as "brakes" on the glaciers that flow into them. The results also suggest that climate warming can lead to rapid sea level rise.

Large ice shelves in the Antarctic Peninsula disintegrated in 1995 and 2002, as a result of climate warming. Almost immediately after the 2002 Larsen B ice shelf collapse, researchers observed nearby glaciers flowing up to eight times faster than they did prior to the break-up. The speed-up also caused glacier elevations to drop, lowering them by up to 38 meters [125 feet] in six months.

"Glaciers in the Antarctic Peninsula accelerated in response to the removal of the Larsen B ice shelf," said Eric J. Rignot, a JPL researcher who is lead author of one of the studies. "These two papers clearly illustrate, for the first time, the relationship between ice shelf collapses caused by climate warming and accelerated glacier flow." Rignot’s study used data from the European Space Agency’s European Remote Sensing Satellites (ERS) and the Canadian Space Agency’s RADARSAT satellite.

"If anyone was waiting to find out whether Antarctica would respond quickly to climate warming, I think the answer is yes," said Theodore A. (Ted) Scambos, an NSIDC glaciologist who is lead author of the second study. "We’ve seen 150 miles [240 kilometers] of coastline change drastically in just 15 years." Scambos’s paper used data from Landsat 7 and ICESat, a NASA laser altimetry mission launched in 2003. Landsat 7 is jointly run by NASA and the United States Geological Survey.

The Rignot and Scambos papers illustrate relationships between climate change, ice shelf break-ups, and increased flow of ice from glaciers into the oceans. Increased flow of land ice into the oceans contributes to sea level rise. While the Larsen area glaciers are too small to affect sea level significantly, they offer insight into what will happen when climate change spreads to regions further south, where glaciers are much larger.

Scambos and his colleagues used five Landsat 7 images of the Antarctic Peninsula from before and after the Larsen B break-up. The images revealed crevasses on the surfaces of glaciers, which were used as markers in a computer-matching technique for tracking motion between image pairs. By following the patterns of crevasses from one image to the next, the researchers were able to calculate velocities of the glaciers. The surfaces of glaciers dropped rapidly as the flow sped up, according to ICESat measurements.

"The thinning of these glaciers was so dramatic that it was easily detected with ICESat, which can measure elevation changes to within an inch or two [several centimeters]," said Christopher A. Shuman, a GSFC researcher and a co-author on the Scambos paper. The Scambos study examined the period right after the Larsen B ice shelf collapse, to try to isolate the immediate effects of ice shelf loss on the glaciers.

Rignot’s study used RADARSAT to take monthly measurements that are ongoing. RADARSAT radar sends out signals and tracks their return after they bounce from snow and ice surfaces. Radar is not limited by clouds, while Landsat images require clear skies. RADARSAT can therefore provide continuous and broad velocity information of the ice.

According to Rignot’s study, the Hektoria, Green, and Evans glaciers flowed eight times faster in 2003 than they did in 2000. They slowed moderately in late 2003. The Jorum and Crane glaciers accelerated two-fold in early 2003 and three-fold by the end of 2003. Adjacent glaciers where the shelves remained intact showed no significant changes, according to both studies.

The studies were funded by NASA, the National Science Foundation, and the Instituto Antartico Argentino.

Harvey Leifert | AGU
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

Gene therapy shows promise for treating Niemann-Pick disease type C1

27.10.2016 | Life Sciences

Solid progress in carbon capture

27.10.2016 | Power and Electrical Engineering

More VideoLinks >>>