sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery

 

Sail-World.com : New Antarctic seabed sonar images reveal clues to sea-level rise

New Antarctic seabed sonar images reveal clues to sea-level rise

British Antarctic Survey ©    Click Here to view large photo

Motorway-sized troughs and channels carved into Antarctica’s continental shelves by glaciers thousands of years ago could help scientists to predict future sea-level rise according to a report in the journal Geology this month (May).

Using sonar technology from onboard ships, scientists from British Antarctic Survey (BAS) and the German Alfred Wegener Institute (AWI) captured the most extensive, continuous set of images of the seafloor around the Amundsen Sea embayment ever taken. This region is a major drain point of the West Antarctic Ice Sheet (WAIS) and considered by some scientists to be the most likely site for the initiation of major ice sheet collapse.


The sonar images reveal an ‘imprint’ of the Antarctic ice sheet as it was at the end of the last ice age around 10 thousand years ago. The extent of ice covering the continent was much larger than it is today. The seabed troughs and channels that are now exposed provide new clues about the speed and flow of the ice sheet. They indicate that the controlling mechanisms that move ice towards the coast and into the sea are more complex than previously thought.

Rob Larter -  British Antarctic Survey?nid=56671 ©  
Lead author Rob Larter from British Antarctic Survey said, 'One of the greatest uncertainties for predicting future sea-level rise is Antarctica’s likely contribution. It is very important for scientists and our society to understand fully how polar ice flows into the sea. Indeed, this issue was highlighted in 2007 by the Intergovernmental Panel on Climate Change (IPCC). Our research tells us more about how the ice sheet responded to warming at the end of the last ice age, and how processes at the ice sheet bed controlled its flow. This is a big step toward understanding of how the ice sheets are likely to respond to future warming.’

Sonar map showing sea bed features -  British Antarctic Survey?nid=56671 ©

Background

For the past 20 years scientists studying the Greenland and Antarctic ice sheets have used a range of technologies, including satellite images, ice-penetrating radar and other techniques to monitor the movement of ice as it flows from Antarctica’s interior towards the coast.

Science teams often work in remote and extreme locations to measure change in their attempts to understand their likely contribution to global sea-level rise.

This work is the result of a collaboration between scientists onboard two research cruises in 2006 – Jan-Feb BAS ship RRS James Clark Ross; Feb-Mar onboard AWI ship RV Polarstern. Ship-borne research cruises provide crucial information about Antarctica’s ice sheet and climate history. This data combined with that from other satellite and ground-based studies help provide answers to big environmental questions that are relevant to people all over the world.

The area of the Amundsen Sea embayment surveyed was 9950 km2. This is equal to -
- Nearly half the size of Wales (20,799 sq.km)
- Nearly the size of Yorkshire (11,903 sq.km, since 1991)
- Larger than Norfolk and Suffolk combined (9172 sq.km)

In the western Amundsen Sea embayment three 17-39 km wide troughs extend seaward from the modern ice shelf front. This is roughly with width of the English Channel. Individual streamlined features carved into the seabed are about as wide as a motorway.

Ice sheet
The Antarctic ice sheet retreated to near its present limit around 10 thousand years ago. It is the layer of ice up to 5000 m thick covering the Antarctic continent. It is formed from snow falling in the interior of the Antarctic which compacts into ice. The ice sheet slowly moves towards the coast, eventually breaking away as icebergs which gradually melt into the sea.

The ice sheet covering East Antarctica is very stable, because it lies on rock that is above sea level and is thought unlikely to collapse. The West Antarctic is less stable, because it sits on rock below sea level.

Ice shelf
An ice shelf is a thick (100-1000 m), floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are found in Antarctica, Greenland and Canada only.

Glacier
Just as rivers collect water and allow it to flow downhill a glacier is actually a 'river' of ice. A glacier flows much more slowly than river. Rivers of ice within ice sheets account for most of the drainage into the oceans.

Continental shelf
The relatively shallow (generally up to 200 meters) seabed surrounding a continent where the depth gradually increases before it plunges into the deep ocean. Around Antarctica the continental shelf is up to 1600 m deep as a result of millions of years of glacial erosion. The deepest parts of the Antarctic continental shelf are near the present ice margin and depths generally decrease offshore.

The Cambridge-based British Antarctic Survey (BAS) is a world leader in research into global environmental issues. With an annual budget of around £45 million, five Antarctic Research Stations, two Royal Research Ships and five aircraft, BAS undertakes an interdisciplinary research programme and plays an active and influential role in Antarctic affairs. BAS has joint research projects with over 40 UK universities and has more than 120 national and international collaborations. It is a component of the Natural Environment Research Council.

More information about the work of the Survey can be found at: www.antarctica.ac.uk





by British Antarctic Survey media

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=56671

4:52 AM Tue 12 May 2009 GMT






Click here for printer friendly version
Click here to send us feedback or comments about this story.

Click for further information on
Environment and the ocean

Related News Stories:

27 Nov 2013  World Oceans Day appeals for funds
16 Nov 2013  Gigantic iceberg sails north from the Antarctic
09 Nov 2013  Sailing and swimming with manatees - Oceans Watch Essay
01 Nov 2013  OceansWatch: cruising sailors give something back in the South Pacific
23 Oct 2013  'The Ocean is Broken' - without fish, there can be no birds
13 Oct 2013  PlanetSolar reaches Paris after successful ocean study
02 Oct 2013  Monaco Yacht Show goes Green
07 Sep 2013  Great Pacific Garbage Patch - the real story
03 Sep 2013  World's largest solar yacht drops anchor after marine science quest
25 Aug 2013  Boat owners: cover vessels to deter seagulls
MORE STORIES ...

News - USA and the World

































































International Moth Worlds: Rashley ahead as Aussies close in by Mark Jardine / YachtsandYachting.com,


ISAF Youth Match Racing Worlds - American unbeatable on day 1
RS Feva World Championships - All set at Yacht Club de Carnac
ISAF Rolex World Sailor of the Year Awards - Nominations now open
BIC Techno 293 Worlds - Steady winds on day 2 + Video
29er North American Open Championship - Qualifying series wraps up
Opening ceremony O'pen Bic World Cup, Travemunde Week, Germany
Six Metre Europeans - Wind fails to make an appearance on day 2
Edgartown Race Weekend - Let the sailing (and good times) begin
ISAF Youth Match Racing World Championship - Action commences July 23
International Moth Worlds - Mothballed on day 4 + Video
Spirits high as Team Alvimedica completes Transatlantic crossing
Gladwell's Line: A change of direction needed in the America's Cup *Feature
29er North American Championship - Day 1 in Kingston
Red Bull 49erFX: First look at the Olympic sailing venue at Rio
Fuerteventura Kiteboarding Grand Slam - Classic conditions on day 3
NYYC Race Week Part II images by Rolex/Daniel Forster
Drowning or electric shock? What you need to know to help save a life
BIC Techno 293 Worlds 2014 - Day 1
Six Metre European Championship - Blazing sunshine on opening day
National Sailing Hall of Fame to present Lifetime Achievement Award
International Moth Worlds: Greenhalgh and Rashley tied at the top   
PWA Pozo World Cup - Fantastic finale determines winners   
Six Metre Class British Open Championship - Llanoria and Valhalla win   
Anna Tunnicliffe set to compete at the CrossFit Games   
America's Cup: Oracle Team USA holds foiling camp at Wangi SC   
Volvo Ocean Race: Abu Dhabi OR completes double Atlantic crossing   
Volvo Ocean Race: Team SCA has a 'pull through day' off the Canaries   
No tiller sailing - how to steer using just the sails + Video   
International Moth Worlds: Three bullets in a row for Greenhalgh   
U.S. Junior Women’s Singlehanded Championship - Sophia Reineke wins   
BIC Techno 293 Worlds 2014 - Day 0 Opening   
Fuerteventura World Cup - Slalom action highlights day 2   
2014 Governor's Cup - Sam Gilmour of RFBYC victorious again   
Farr 40 West Coast Champ - Skipper Alberto Rossi leads Enfant Terrible   
Flying Dutchman World Championships - Magyars are the Masters   
Final day shakes up standings at Cape Panwa Hotel Phuket Raceweek   
2014 -15 Volvo Ocean Race: Team Alvimedica pushing towards Southampton   
NYYC Race Week - Saving the best for last   
VX One North American Championship - Chris Alexander commands   
2014 Cape Panwa Hotel Phuket Raceweek - Waiting game on Day 3   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL WAS US
LocalAds   DE  ES  FR  IT