Subscribe to our free daily newsletters
  Space Industry and Business News  




Subscribe to our free daily newsletters



EARTH OBSERVATION
TerraSAR-X-Image Of The Month: Calving Icebergs On Queen Maud Land

A small island obstructs the constant flow of the ice shelf on Queen Maud Land - it is the lighter area at the bottom left of the image. From September 2010 until it broke off, Iceberg A 62 was connected to the Fimbul Ice Shelf by a mere 800-metre-wide bridge. Two fissures in the ice from different sides of the bridge approached one another until the break occurred. The images transmitted by the radar satellite TerraSAR-X over a long period of time should enable researchers to achieve a better understanding of how icebergs calve. Until now, glaciologists have not been able to predict where and how much ice will break away each year. Credit: DLR.
by Manuela Braun
Hamburg, Germany (SPX) Feb 10, 2011
If the city of Bonn were located on the edge of the Fimbul Ice Shelf, in the Antarctic, its inhabitants would now be embarking on a journey through the Antarctic Circumpolar Current. An iceberg with a surface area of 120 square kilometres - the size of Bonn - has calved in the Atlantic.

Glaciologists at Hamburg University's Climate Campus have been using the German Aerospace Center radar satellite, TerraSAR-X, to observe the area from an altitude of 500 kilometres and gain a better understanding of how icebergs like this will calve in the future.

A small island obstructs the constant flow of the ice shelf on Queen Maud Land - it can be seen as a lighter area at the bottom left of the image. "The ice shelf gets caught here as if trying to pass over a bed of nails," explains glaciologist Angelika Humbert from the Climate Campus.

"Once the ice passes the island, the tension on its surface is extraordinarily high." At the same time, the ice front pulls on the ice shelf; if the tension is high enough, a fissure forms.

"But we are still unsure about the exact mechanism of the calving process." How does an iceberg form? What factors are involved? Forces such as tides, ocean currents and storms gently but constantly pull on the edges of the ice. At the same time, the ice is flowing under its own weight.

"It's almost like honey spreading itself over a slice of bread." The masses of ice take their time in this process; the ice shelf slowly moves forwards for decades before calving occurs. "We do know that the way in which the ice creeps forward has a significant influence on the formation of icebergs, but the extent to which break-offs from the edge of the ice depend on tides or various material parameters is still not clear."

Cracks on both sides
From September 2010 until it broke off, Iceberg A 62 was connected to the Fimbul Ice Shelf by a mere 800-metre-wide bridge. Two fissures in the ice, one on each side, approached one another until the break occurred.

The images obtained by TerraSAR-X over an extended period of time should enable researchers to achieve a better understanding of how icebergs calve. Until now, glaciologists have not been able to predict how much ice will break off each year or where.

"Calving is a long process culminating in one single event," explains Angelika Humbert. "We can't derive a general pattern from it." It is for this reason that the satellite data is fed into computer simulations of the fracture mechanics and flow mechanisms of ice masses.

A fissure is then triggered in the virtual ice shelf, and its expansion and calving simulated. The researchers then compare these with more up-to-date satellite data to determine how close the simulation is to reality. The aim is to develop a bigger and improved basis for simulated scenarios.

Alerting the local team
The Fimbul Ice Shelf is perfect for the glaciologists' research: "This ice shelf has a very large number of fissures. The ice moves approximately 800 metres a year in this part of the Antarctic. It's not a risk-free research subject," says Angelika Humbert. She used the TerraSAR-X images to schedule field measurements to be carried out by a team from the Norwegian Polar Institute.

In October 2010 these researchers were finally able to explore the ice shelf, while Angelika Humbert analysed the latest radar images and alerted her colleagues in the Antarctic all the way from Germany: "All those involved were on the edge of their seats - is this thing going to calve or not?" The glaciologist was worried about the iceberg breaking off then and there, and the team quickly getting to safety if the calving caused other fissures to spread.

"The worst fissures are the very narrow ones," says Angelika Humbert. "It's hard to see these on most satellite images, but they show up very clearly on TerraSAR-X images. The radar satellite operates with an incredibly high resolution, crucial for the study of ice dynamics."



Share This Article With Planet Earth
del.icio.usdel.icio.us DiggDigg RedditReddit
YahooMyWebYahooMyWeb GoogleGoogle FacebookFacebook



Related Links
Hamburg University
Earth Observation News - Suppiliers, Technology and Application



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


EARTH OBSERVATION
NASA's Earth Data System Earns Praise
Greenbelt MD (SPX) Feb 09, 2011
If you're distributing 412 million data products in a year to more than 1.1 million users, how do you ever make sure people are getting what they want? The Earth Observing System Data and Information System (EOSDIS) Project based at Goddard Space Flight Center, Greenbelt, Md., came up with a simple formula: They ask. EOSDIS is the network of Earth science data centers that process, store, ... read more







EARTH OBSERVATION
Floppy discs out, Blu-rays in -- Greece revises stats

Yap.TV a virtual living room for show lovers

Nokia needs to make Windows phones hip

Cartoon news is the future: Hong Kong media mogul

EARTH OBSERVATION
USAF Selects Northrop Grumman To Research SOA IT For Integrated Air And Space Command And Control

Boeing Tests New Ka-band SATCOM Antenna System

Raytheon to supply radios to Aussie army

RAF Begin Training With US On Intelligence Aircraft

EARTH OBSERVATION
Vandenberg Launches Minotaur One

ISRO Awaits Data On GSLV Failure

BrahMos Aerospace To Make Cryogenic Engines For Indian Rockets

Activities At Esrange Space Center 2011

EARTH OBSERVATION
Russia To Launch Glonass Satellite Feb 24

SkyTraq Introduces Low-Power High-Performance GLONASS/GPS Receiver

JAXA Selects Spirent For Multi-GNSS Testing

Nokia in maps tie-up with China's Sina, Tencent

EARTH OBSERVATION
Brown Kills Effort To Move Aeronautic Research Away From NASA

Boeing Submits Final NewGen Tanker Proposal To US Air Force

India closes in on fighter aircraft deal

Boeing, EADS submit final bids for US tanker deal

EARTH OBSERVATION
Silicon Oxide Gets Into The Electronics Action On Computer Chips

Engineers Grow Nanolasers On Silicon, Pave Way For On-Chip Photonics

UMD Advance Lights Possible Path To Creating Next Gen Computer Chips

Samsung offers full refund for Intel chip

EARTH OBSERVATION
TerraSAR-X-Image Of The Month: Calving Icebergs On Queen Maud Land

TRMM Satellite Totaled Cyclone Yasi's Heavy Rainfall In Queensland

A Snowy US Panorama By Satellite

NASA's Earth Data System Earns Praise

EARTH OBSERVATION
Baltic nations optimistic on cleanup pledges

Spanish prosecutors, ecologists urge action on pollution

Spanish cities take action as pollution levels soar

Scientists Urge New Research Policies In Wake Of Gulf Disaster


The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement