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

 

Sail-World.com : Icelandic current could influence ocean's response to changes

Icelandic current could influence ocean's response to changes

'Buoyant spheres will hold the moorings upright when they are placed in the North Icelandic Jet during the upcoming field program to measure the characteristics of the current.'    Woods Hole Oceanographic Institution (WHOI) ©

Woods Hole Oceanographic Institution’s international team of researchers, which includes physical oceanographers, has confirmed the presence of a deep-reaching ocean circulation system off Iceland that could significantly influence the ocean’s response to climate change in previously unforeseen ways.

The current, called the North Icelandic Jet (NIJ), contributes to a key component of the Atlantic Meridional Overturning Circulation (AMOC), also known as the 'great ocean conveyor belt,' which is critically important for regulating Earth's climate. As part of the planet’s reciprocal relationship between ocean circulation and climate, this conveyor belt transports warm surface water to high latitudes where the water warms the air, then cools, sinks, and returns towards the equator as a deep flow.

Crucial to this warm-to-cold oceanographic choreography is the Denmark Strait Overflow Water (DSOW), the largest of the deep, overflow plumes that feed the lower limb of the conveyor belt and return the dense water south through gaps in the Greenland-Scotland Ridge.

Northern part of Denmark Strait showing the location of the newly discovered deep current in relation to the known existing pathway of dense water. -  Jack Cook, Woods Hole Oceanographic Institution  

For years it has been thought that the primary source of the Denmark Overflow is a current adjacent to Greenland known as the East Greenland Current. However, this view was recently called into question by two oceanographers from Iceland who discovered a deep current flowing southward along the continental slope of Iceland. They named the current the North Icelandic Jet and hypothesized that it formed a significant part of the overflow water.

Now, in a paper published in the Aug. 21 online issue of the journal Nature Geoscience, the team of researchers—including the two Icelanders who discovered it—has confirmed that the Icelandic Jet is not only a major contributor to the DSOW but 'is the primary source of the densest overflow water.'

'In our paper we present the first comprehensive measurements of the NIJ,' said Robert S. Pickart of WHOI, one of the authors of the study. 'Our data demonstrate that the NIJ indeed carries overflow water into Denmark Strait and is distinct from the East Greenland Current. We show that the NIJ constitutes approximately half of the total overflow transport and nearly all of the densest component.

The researchers used a numerical model to hypothesize where and how the NIJ is formed. 'We’ve identified a new paradigm,' he said. 'We’re hypothesizing a new, overturning loop' of warm water to cold.

The North Icelandic Jet shown in cross-section view adjacent to the continental slope of Iceland. -  Jack Cook, Woods Hole Oceanographic Institution  

The results, Pickart says, have 'important ramifications' for ocean circulation’s impact on climate. Climate specialists have been concerned that the conveyor belt is slowing down due to a rise in global temperatures. They suggest that increasing amounts of fresh water from melting ice and other warming-related phenomena are making their way into the northern North Atlantic, where it could freeze, which would prevent the water from sinking and decrease the need for the loop to deliver as much warm water as it does now. Eventually, this could lead to a colder climate in the northern hemisphere.

While this scenario is far from certain, it is critical that researchers understand the overturning process, he said, to be able to make accurate predictions about the future of climate and circulation interaction. 'If a large fraction of the overflow water comes from the NIJ, then we need to re-think how quickly the warm-to-cold conversion of the AMOC occurs, as well as how this process might be altered under a warming climate,' Pickart said.

'These results implicate local water mass transformation and exchange near Iceland as central contributors to the deep limb of the Atlantic Meridional Overturning Circulation, and raise new questions about how global ocean circulation will respond to future climate change,' said Eric Itsweire, program director in the U.S. National Science Foundation (NSF)’s Division of Ocean Sciences, which funded the research.

The Research Council of Norway also funded the analysis of the data.

Pickart and a team of scientists from the U.S., Iceland, Norway, and the Netherlands are scheduled to embark on Aug. 22 on a cruise aboard the WHOI-operated R/V Knorr to collect new information on the overturning in the Iceland Sea.

R/V Knorr navigates through the Iceland Sea while taking measurements of the North Icelandic Jet. -  Woods Hole Oceanographic?nid=87732 Institution (WHOI) ©  

'During our upcoming cruise on the Knorr we will, for the first time, deploy an array of year-long moorings across the entire Denmark Strait to quantify the NIJ and distinguish it from the East Greenland Current,' Pickart said. 'Then we will collect shipboard measurements in the Iceland Sea to the north of the mooring line to determine more precisely where and how the NIJ originates.'

In addition to Pickart, authors of the Nature Geoscience study include Michael A. Spall, and Daniel J. Torres of WHOI, lead author Kjetil Våge, a graduate of the MIT-WHOI joint program now with University of Bergen, Norway, Svein Østerhus and Tor Eldevik, also of the University of Bergen, Norway, and Héðinn Valdimarsson and Steingrímur Jónsson—the two discoverers of the NIJ—of the Marine Research Institute in Reykjavik, Iceland.

Woods Hole Oceanographic Institution website

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the ocean and its interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.




by Woods Hole Oceanographic Institution

  

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

http://www.sail-world.com/index.cfm?nid=87732

9:56 PM Thu 25 Aug 2011 GMT






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


News - USA and the World









Audi Melges 20 World Championship - Classic Garda conditions on day 2 by International Audi Melges 20 Class Association,


















Audi Melges 20 World Championship - Alessandro Rombelli's 'STIG' leads by International Audi Melges 20 Class Association,




























Aldo Alessio Regatta - Three days of tight racing by Erik Simonson, Pressure-Drop.US,










Sailing Champions League - which is Europe's best sailing club? by Dan Ibsen & the Sail-World team, Copenhagen


Weta fun at the Wine & Roses Regatta
Extreme Sailing Series: The Wave, Muscat claims victory on Cardiff Bay
International 14 World Championships 2015: Not just for boys
Rio de Janeiro achieves 50% treatment of sewage outflow *Feature
2014 AWT Quatro Desert Showdown - Event memorable videos
2014 18' Skiff Int Regatta: Day 1 at San Francisco - Reversal on beach
Emirates Team NZ: Last race boost cannot save team from table bottom
PWA Alacati World Cup - Furious slalom is upon us
J/111 World Championships - The Winner is Shmokin Joe!
J/24 US National Championship - Victory for Will Welles’ Cougar
Extreme Sailing Series: View the Final Day's action - Replay
NYYC Grandmasters Team Race - Reign continues for Noroton Yacht Club
WSSR announces new World Record Around Britain and Ireland
IFDS Worlds 2014 - Final day photos by Tim Wilkes
2014 Detroit Cup - Morvan wins
Newport Bucket Regatta 2014 -Images by George Bekris
IFDS Worlds 2014 - Final report: USA qualifies for Rio 2016
Extreme Sailing Series: Absent With-Out Leave – Ben Ainslie Racing
2014 IFDS World Championship - New champions claim medals
2014 IFDS World Championships - Sunday’s race images by Tim Wilkes
Shark World Championships underway in Toronto   
Anna Tunnicliffe: Alinghi second o'all - Extreme Sailing Series, Day 3   
Formula Kite World Championships - Nocher and Bridge crowned Champions   
Emirates Team NZ: Frustrating Day 3 in Extreme Sailing Series, Cardiff   
Extreme Sailing Series: Light winds help The Wave Muscat - Day 3   
Extreme Sailing Series 2014 Act five - Absent without leave – the wind   
IFDS Worlds 2014 - Images: Race day five   
Herreshoff Classic Regatta 2014 - Images by Ingrid Abery   
Youth Olympics - Gold to Argentinean and Chinese Techno 293 racers   
Youth Olympics Games Nanjing - Double Youth Olympic Gold for Singapore   
Sevenstar Round Britain and Ireland Race 2014 - Two Handers celebrate   
Audi Melges 20 U.S. National Championship 2014 - Brazilian dance party   
IFDS Disabled Sailing Worlds Day 5 - USA fighting for Rio 2016 Berths   
J/111 World Championship 2014 - Day 4: Shmokin Joe consolidates lead   
Anna Tunnicliffe: Alinghi on top - Extreme Sailing Series, Day 2   
2014 IFDS World Championships - Breezy frustrations   
2014 Detroit Cup - Down to the final four   
Sevenstar Round Britain and Ireland Race - Every finisher's a winner   
2014 49er, 49er FX, Nacra 17 U.S. National Championship - Day 2   
J/24 US National Championship - Will Welles leaps into lead   


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