Posted on 08/21/2011 1:42:24 PM PDT by decimon
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."
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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.
Running AMOC ping.
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”
Is it originating from Kennebunkport?
BUSH’S FAULT!!
I had a hunch those Icelanders were up to something! First the volcanoes, now this.
Translation: "We're making sh!t up."
ABOUT FACE!
And, it's usually the Amish. Go figure.
“Newly discovered?” Does that also mean it just BEGAN yesterday??? So it hadn’t affected anything before cause it hadn’t been discovered????
... or, newly discovered monkeys flying with giant fans out of Algore's butt could reverse global warming.
Thanx for the ping decimon !
And didn't the world's monetary problems begin in Iceland as well?
I wonder how many other evils they're causing? I believe they had some riots a few years back also. Not sure if that was before or after the French "urban" (i.e., Muslim) youth developed car-burning to a fine art.
And didn't the world's monetary problems begin in Iceland as well?
The Icelanders started all monetary problems with cut-rate airfares between the US and Europe. They circumvented price-fixed fares by not flying direct but stopping in Iceland. That obviously led to the housing bubble decades later.
That almost sounds like the Atlantic is a self-correcting closed system (ie, negative feedback) -
But that can't be right - think how many academic papers would have to be re-written - it has to to be all our evil SUVs ruining Gaia.../S
IOW they still don’t know jack. Hereby all predictions and policies should not be used
That ain’t Iceland.
I just said she was monitoring the current! So she’s in Bermuda and has a telescope. I spoke to her and she said she will get back to you! She also is giving you a tip of the hat. BTW those are clouds over her right shoulder.
I always worry about those shots from behind... she might have the face of Helen Thomas. =8-0>
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