May 18, 2009
New North Atlantic circulation path found
U.S. scientists say they have discovered a new pathway for the global ocean circulation known as the Great Ocean Conveyor.
Researchers from the Woods Hole Oceanographic Institution and Duke University said the conveyor belt paradigm says the Gulf Stream-warmed ocean releases heat to the atmosphere in the northern North Atlantic, leaving ocean water colder and denser as it moves north. The cold waters then sink and flow southward along the
deep western boundary current that hugs the continental slope from Canada to the equator. To replace the down-flowing water, warm surface waters from the tropics are pulled northward along the conveyor's upper limb.
But in their new study, the scientists said they determined much of the southward flow of cold water from the Labrador Sea moves not along the deep western boundary current, but along a previously unknown path in the interior of the North Atlantic.
And since the cold southward-flowing water is thought to influence and perhaps moderate human-caused climate change, the researchers say their finding might impact the work of global warming forecasters.
The study led by WHOI senior scientist Amy Bower and Duke Professor Susan Lozier appears in the journal Nature.