Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antarctic Glaciers Surge When Ice Shelves Collapse

22.09.2004


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:
http://www.agu.org
http://www.nasa.gov

More articles from Earth Sciences:

nachricht Novel method for investigating pore geometry in rocks
18.06.2018 | Kyushu University, I2CNER

nachricht Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Creating a new composite fuel for new-generation fast reactors

20.06.2018 | Materials Sciences

Game-changing finding pushes 3D-printing to the molecular limit

20.06.2018 | Materials Sciences

Could this material enable autonomous vehicles to come to market sooner?

20.06.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>