Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Envisat shows behemoth B-15A iceberg breaking up

08.11.2005


After five years of being the world’s largest free-floating object, the B-15A iceberg has finally broken up off Antarctica’s Cape Adare.



ESA’s Envisat satellite’s Advanced Synthetic Aperture Radar (ASAR) is sensitive to ice, and has been tracking the movement of the drifting ice object since the beginning of this year. Its latest imagery reveals the bottle-shaped iceberg split into nine knife-shaped icebergs and a myriad of smaller pieces on 27-28 October, the largest being formed by fractures along the long axis of the original single iceberg.

Measuring – until last week - around 115 kilometres in length with an area exceeding 2500 square kilometres, the iceberg had apparently run aground off Cape Adare, the northernmost corner of the Victoria Land Coast. This stranding appears to have led to flexing and straining which resulted in the break-up.


"The long knife-shaped pieces suggest the iceberg has split along existing lines of weakness within the iceberg," says Mark Drinkwater of ESA’s Ocean and Ice Unit. "These would have been pre-existing crevasses in the ice shelf."

These new icebergs, named by the US National Oceanic and Atmospheric Administration (NOAA) National Ice Center, will retain their parent’s title: the three largest island-sized pieces have been called B-15M, B-15N and B-15P.

B-15A was the largest remaining section of the even larger B-15 iceberg that calved from the nearby Ross Ice Shelf in March 2000 before breaking up into smaller sections.

Since then its B-15A section drifted into McMurdo Sound, where its presence blocked ocean currents and led to a build-up of sea ice that decimated local penguin colonies, deprived of open waters for feeding. During the spring of this year prevailing currents took B-15A slowly past the Drygalski ice tongue. A full-fledged collision failed to take place, but a glancing blow broke the end off Drygalski in mid-April.

The iceberg sailed on to have a less-destructive close encounter with the Aviator Glacier ice tongue at Lady Newnes Bay before becoming stranded off Cape Adare in mid-October.

Radar monitoring of Antarctic ice

ASAR is extremely useful for tracking changes in polar ice. ASAR can peer through the thickest polar clouds and work through local day and night. And because it measures surface texture, the instrument is also extremely sensitive to different types of ice – so the radar image clearly delineates the older, rougher surface of icebergs from surrounding sea ice, while optical sensors simply show a continuity of snow-covered ice.

Envisat’s ASAR instrument monitors Antarctica in two different modes: Global Monitoring Mode (GMM) provides 400-kilometre swath one-kilometre resolution images, enabling rapid mosaicking of the whole of Antarctica to monitor changes in sea ice extent, ice shelves and iceberg movement.

Wide Swath Mode (WSM) possesses the same swath but with 150-metre resolution for a detailed view of areas of particular interest.

ASAR GMM images are routinely provided to a variety of users including the National Ice Center, responsible for tracking icebergs worldwide.

Mariangela D’Acunto | alfa
Further information:
http://www.esa.int/esaEO/SEMCYK638FE_planet_0.html

More articles from Earth Sciences:

nachricht From volcano's slope, NASA instrument looks sky high and to the future
27.04.2017 | NASA/Goddard Space Flight Center

nachricht Penn researchers quantify the changes that lightning inspires in rock
27.04.2017 | University of Pennsylvania

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

Control of molecular motion by metal-plated 3-D printed plastic pieces

27.04.2017 | Materials Sciences

Move over, Superman! NIST method sees through concrete to detect early-stage corrosion

27.04.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>