sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery
Sail-World.com : Unknown mechanism which breaks up tabular icebergs at sea discovered
Unknown mechanism which breaks up tabular icebergs at sea discovered

'Operation Iceberg'    BBC    Click Here to view large photo

A previously unknown mechanism by which large tabular icebergs break up out at sea, as part of a study carried out on the Peterman Iceberg in Baffin Bay over the summer, has been discovered by an international team of scientists. Scientists observed that the gradual creation of a huge underwater ice foot produced so much buoyancy that it broke large chunks off the main iceberg thus causing the iceberg to slowly disintegrate. This discovery was captured on camera as a film crew followed the expedition for Operation Iceberg, a two part BBC Two series going out this week.

Scientists have long assumed the decay of icebergs was either caused by wave action physically splitting them apart, or by warmer sea water gradually melting them. The truth now appears to be an interesting combination of factors. During the arctic expedition, scientists found that warm surface water, aided by wave action, erodes a deep notch around the edge of the iceberg. This notch is at water level, and the unsupported ice above the notch quickly sloughs away. Over time this creates a large underwater 'ram' or ice foot sticking out which is protected by colder, deeper water. This underwater ram creates so much buoyant upwards pressure that it finds a weak point within the iceberg which then snaps off. This can be a sizeable chunk of ice. During filming for Operation Iceberg, camera crews and scientists were aboard the iceberg when a chunk of ice, 200m by 50m, broke off in this way.

Operation Iceberg - BAS scientist Dr Keith Nicholls -  BBC   Click Here to view large photo

Dr Keith Nicholls of the British Antarctic Survey was on the two week expedition. He argues that the notch is the key start to this process. In the programme he says: 'The reason this iceberg is breaking up really fast in front of us is all about what’s happening at the wave cut in the warm water layer right at the surface.'

Also on the expedition was one of the world leading experts on ice science, Prof Peter Wadhams of Cambridge University, who believes their observation of the process is unique: 'We have discovered a new mechanism. People don’t normally sit beside melting icebergs in a ship. Normally when they come across an iceberg they give it a wide berth. So in a way, we’re the first people to be doing it.'

Alon Stern of New York University was responsible for taking the temperature measurements of the sea water around the iceberg, including key data gathered by the BBC’s dive team. These readings confirmed that the deeper water measured -1.5 degrees Celsius, and was therefore able to protect the ice foot from melting.

Understanding the mechanism by which icebergs break up is important for shipping in the North Atlantic. It is also becoming clear that because of climate change, the number of tabular icebergs in Arctic seas is increasing. Keith Nicholls added: 'In recent years we’ve been seeing a lot more big tabular icebergs come off the Greenland ice sheet and they’re now ending up in Baffin Bay. That’s a change and the only reason that can change is because the climate around Greenland is changing.'

To watch the team in action, tune into Operation Iceberg, at 9pm on BBC Two on Tuesday 30th of October and Thursday first of November.

You can read Dr Keith Nicholls' blog here.

British Antartic Survey website


by British Antarctic survey/BBC Operation Iceberg

  

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

http://www.sail-world.com/index.cfm?nid=103439

10:21 AM Fri 2 Nov 2012GMT


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







News - USA and the World





Volvo Ocean Race: Team Vestas Wind gears up in Alicante by Richard Gladwell/Sail-World.com/nz,






































Soling North American Championship concludes on Lake Erie by Canadian International Soling Association,
























ISAF Sailing World Championships Santander: The overall results +Video
ISAF Sailing Worlds - Four champions crowned as racing wraps up
ISAF Sailing Worlds, Santander - USA finishes Top-10 in 4 classes
Outteridge and Jensen – What doesn’t kill you makes you stronger
ISAF Sailing Worlds, Santander - Giles Scott wins Gold
Santander Worlds - 49ers Burling and Tuke clear ahead
ISAF Sailing Worlds – Live broadcast - Medal races
Starboard Hatteras Wave Jam day 5
WMRT Chicago Match Cup 2014 – GAC Pindar through to the semi-finals
Bart’s Bash 2014 at Royal Hong Kong Yacht Club in Victoria Harbour
Bart's Bash: First event in at Wakatere in New Zealand
ISAF Sailing Worlds Santander 2014 - AUS Laser and 470 Medals + video
2014 Patriot Regatta - U.S. Coast Guard team wins
2014 ISAF Sailing World Championships - Santander - Day 9 highlights
2014 Etchells North American Championship – Day 2
Chicago Match Cup - Top four tour teams tackle tomorrow in semi-finals
470 Men and Women Worlds - Champions decided in Santander
ISAF Sailing Worlds, Santander: 49er and Nacra 17 world titles claimed
ISAF Sailing Worlds - Caleb Paine through to Finn medal race + video
ISAF Worlds - 49er, 49erFX, Finn and Nacra 17 Rio 2016 spots taken
ISAF Sailing Worlds - 470 Women's medal race images by Thom Touw   
ISAF Sailing Worlds, Santander: Scott all set to lift Finn world title   
ISAF Sailing Worlds - 470 Men's medal race images by Thom Touw   
ISAF Sailing Worlds, Santander - Aussies and Austrians claim 470 gold   
ISAF Sailing Worlds, Santander: 470 awards images by Sail-World.com   
ISAF Sailing Worlds, Santander - 470 medal race images by Jesus Renedo   
Annapolis-to-Newport Race - 'What to Expect' Seminar to take place   
Royal Cup Marina Ibiza - No racing on penultimate day   
Belcher takes record fifth 470 World Championship   
ISAF Sailing World Championships - Santander - Day 8 video highlights   
2014 Great Lakes Team Racing Championship about to set off   
2014 Etchells North American Championship - Day 1   
2014 U.S. Multihull Championship - Day 1   
2014 Chicago Match Cup - Repechage top four determined in final flight   
J/24 World Championship - 35th anniversary preview   
470 Men and Women Worlds - Santander medal race line-up confirmed   
ISAF Sailing Worlds, Santander - Day 8 images by Sail-World.com   
Royal Cup Marina Ibiza - Quantum Racing stumbles in coastal race   
ISAF Sailing Worlds, Santander - Americans ready for 470 medal races   
ISAF Sailing Worlds, Santander: Action ramps up with end zone in sight   


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 NEW US
LocalAds   DE  ES  FR  IT