Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Newly discovered Icelandic current could change North Atlantic climate picture

22.08.2011
An international team of researchers, including physical oceanographers from the Woods Hole Oceanographic Institution (WHOI), 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.

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 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.

"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.

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.

Media Relations | EurekAlert!
Further information:
http://www.whoi.edu

More articles from Earth Sciences:

nachricht Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>