Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Iceberg’s end caught by Envisat

11.11.2003


ESA’s Envisat satellite was witness to the dramatic last days of what was once the world’s largest iceberg, as a violent Antarctic storm cracked a 160-km-long floe in two.


Another Envisat instrument known as MERIS acquired this optical image showing B-15A in the Ross Sea on 16 October 2003. The bottle-shaped iceberg can be seen centre. Below it is the Ross Ice Sheet from which the B-15 berg originated in March 2003. Left of B-15A is McMurdo Sound, location of US and New Zealand Antarctic bases.

Credits: ESA 2003


This ASAR image from 6 November 2003 clearly shows the split iceberg. The larger piece of B-15A retains the original name, while the other piece is called B-15J. Left of B-15A can be seen land - including the famous McMurdo Dry Valleys, and behind them the Transantarctic Mountains. Top of the picture is the floating Drygalski Ice Tongue, an example of ice draining from the David Glacier into the sea at a minimum rate of 150 metres a year.

Credits: ESA 2003



A series of Envisat Advanced Synthetic Aperture Radar (ASAR) instrument images acquired between mid-September and October record how the bottle-shaped iceberg B-15A was split by the onslaught of powerful storms, waves and ocean currents as its own weight kept it fixed on the floor of Antarctica’s Ross Sea.

ASAR is especially useful for polar operations because its radar signal can pierce thick clouds and works through both day and night. Radar imagery charts surface roughness, so can easily differentiate between different ice types. Old ice – as on the surface of B-15A – is rougher than newly formed ice.


B-15A began its existence as B-15 in March 2000 - with an area of 11,655 sq km it was the world’s largest known iceberg. This Jamaica-sized floe was created when it broke away from the Ross Ice Shelf. The initial monster berg split into numerous pieces shortly afterwards, with the largest piece designated B-15A.

Like a wall of ice, B-15A remained a stubborn presence for the next two and a half years, diverting ocean currents. This caused increased ice around Ross Island that disrupted breeding patterns for the local penguin colony and required extra icebreaker activity to maintain shipping access to the US base at McMurdo Sound.

B-15A’s end came in sight on 7 October this year, as 120 kph winds buffeted the grounded iceberg during a storm. Two cracks ran into the heart of the iceberg from opposite ends until finally the entire berg gave way.

The larger of the two new pieces has inherited the name B-15A, and the smaller berg named B-15J. They remain largely locked in place, some 3,800 kilometres south of New Zealand. The bergs could persist there for many years – a GPS station has been placed on the 3,496 sq km B-15A to enable study of its future progress.

Despite events such as these there is so far no conclusive evidence as to whether polar ice is actually thinning. Next year will see the launch of ESA’s CryoSat mission, a dedicated ice-watching satellite designed to map precise changes in the thickness of polar ice-sheets and floating sea-ice.

CryoSat will be the first satellite to be launched as part of the Agency’s Living Planet Programme. This small research mission will carry a radar altimeter that is based on a heritage from existing instruments, but with several major enhancements to improve the measurement of icy surfaces.

By determining rates of ice-thickness change CryoSat will contribute to our understanding of the relationship between the Earth’s ice cover and global climate.

Frédéric Le Gall | ESA
Further information:
http://www.esa.int/export/esaSA/SEMCPWWLDMD_earth_0.html

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>