Please select your home edition
Edition
Bakewell-White Yacht Design

Unknown mechanism which breaks up tabular icebergs at sea discovered

by British Antarctic survey/BBC Operation Iceberg on 2 Nov 2012
Operation Iceberg BBC
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.


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.

http://www.antarctica.ac.uk/" target="_blank">British Antartic Survey website

InSunSport - NZBarz Optics - San Juan Worlds Best EyewearAncasta Ker 40+ 660x82

Related Articles

Zhik sailors win 17 sailing medals at 2016 Olympic Regatta
The 2016 Olympic games are over and what a Games they have been - Zhik sailors dominated Zhik sailors won almost 60% of the medals contested at Rio de Janeiro. It was a regatta which tested sailors and gear - with one day being the most severe conditions ever experienced at an Olympic regatta. For the Zhik team riders on the waters of Rio, four years and more of hard work and dedication have paid off for many.
Posted on 29 Aug
Rio official murdered ten months before the Olympics
Rio de Janeiro is a troubled city and a reeling Olympic host, but it will always have beautiful Guanabara Bay. Does an unsolved murder of an official in Rio in charge of cleaning up Guanabara Bay say a lot about the state of platy in the magical city? Priscilla Pereira was murdered 10 months ago and the thinking is that she was murdered in relation to her work
Posted on 31 Jul
WHO statement on Zika virus
The third meeting of the EC convened by the Director-General under IHR 2005 regarding microcephaly and Zika virus The third meeting of the Emergency Committee (EC) convened by the Director-General under the International Health Regulations (2005) (IHR 2005) regarding microcephaly, other neurological disorders and Zika virus was held by teleconference on 14 June 2016, from 13:00 to 17:15 Central European Time.
Posted on 16 Jun
Atlantic Cup 2016 - a race with an environmental commitment
The Atlantic Cup continues to further its mission for the 2016 race by examining the global economic impact of the ocean The Atlantic Cup continues to further its mission for the 2016 race by examining the global economic impact of the ocean and how an unhealthy ocean can affect the economy.
Posted on 7 Apr
Zika virus situation report
From 1 January 2007 to 16 March 2016, Zika virus transmission was documented in a total of 59 countries and territories. From 1 January 2007 to 16 March 2016, Zika virus transmission was documented in a total of 59 countries and territories. Cuba and Dominica are the latest to report autochthonous (local) transmission of Zika virus on 14 and 15 March, respectively. Five of these countries and territories reported a Zika virus outbreak that is now over.
Posted on 2 Apr
Have Norway scientists solved the Bermuda Triangle mystery?
The Bermuda Triangle has been said to have claimed numerous ships and aircraft over the years The Bermuda Triangle has been said to have claimed numerous ships and aircraft over the years, and everything from aliens to remnants from the lost island of Atlantis have been fingered as the culprits.
Posted on 15 Mar
Cyclone Winston Relief Fund – Help the people of Fiji
Sea Mercy is sending volunteer fleet of small and large vessels, loaded with shelter, food and medical supplies to Fiji. Sea Mercy is once again sending our volunteer fleet of small and large vessels, loaded with shelter, food, water and medical supplies and teams to Fiji.
Posted on 27 Feb
Flying Scot Atlantic Coast Champs - Hanson Medals awarded for rescues
US Sailing Safety at Sea Committee awarded the Arthur B. Hanson Rescue Medals to eight boats for their heroic efforts The US Sailing Safety at Sea Committee awarded the Arthur B. Hanson Rescue Medals to eight boats for their heroic efforts when a microburst storm hit the 2015 Flying Scot Atlantic Coast Championship, hosted by the Blackbeard Sailing Club, in New Bern, NC on September 12.
Posted on 2 Feb
Eco-warriors Sea-Bin crowd sharing critical stage with nine days to go
The automated marina cleaning SeaBin project has raised 86% of their target with 9 days left. The automated marina cleaning SeaBin project has raised $198,020 of $230,000.00 with nine days left on their Indiegogo crowdfunding platform, but they need more help now.
Posted on 29 Dec 2015
Higher levels of Fukushima Cesium detected offshore
Scientists monitoring the spread of radiation in the ocean from the Fukushima nuclear accident report Scientists monitoring the spread of radiation in the ocean from the Fukushima nuclear accident report finding an increased number of sites off the US West Coast showing signs of contamination from Fukushima. This includes the highest detected level to date from a sample collected about 1,600 miles west of San Francisco.
Posted on 6 Dec 2015