NASA Reports Substantial Weakening Of N. Atlantic Current In Late 1990s

[hatrack]

"A North Atlantic Ocean circulation system weakened considerably in the late 1990s, compared to the 1970s and 1980s, according to a NASA study.

Sirpa Hakkinen, lead author and researcher at NASA's Goddard Space Flight Center, Greenbelt, Md. and co-author Peter Rhines, an oceanographer at the University of Washington, Seattle, believe slowing of this ocean current is an indication of dramatic changes in the North Atlantic Ocean climate. The study's results about the system that moves water in a counterclockwise pattern from Ireland to Labrador were published on the Internet by the journal Science on the Science Express Web site at:

http://www.sciencexpress.org
or
http://www.aaas.org

The current, known as the sub polar gyre, has weakened in the past in connection with certain phases of a large-scale atmospheric pressure system known as the North Atlantic Oscillation (NAO). But the NAO has switched phases twice in the 1990s, while the subpolar gyre current has continued to weaken. Whether the trend is part of a natural cycle or the result of other factors related to global warming is unknown.

"It is a signal of large climate variability in the high latitudes," Hakkinen said. "If this trend continues, it could indicate reorganization of the ocean climate system, perhaps with changes in the whole climate system, but we need another good five to 10 years to say something like that is happening." Rhines said, "The sub polar zone of the Earth is a key site for studying the climate. It's like Grand Central Station there, as many of the major ocean water masses pass through from the Arctic and from warmer latitudes. They are modified in this basin. Computer models have shown the slowing and speeding up of the subpolar gyre can influence the entire ocean circulation system."

EDIT

http://www.evworld.com/view.cfm?section=communique&newsid=5467

[Boomer]

1. And on a similar note...

Climate theories run hot and cold
UW scientists look at arctic clues

Using satellites and an innovative robotic underwater probe designed at the University of Washington, Peter Rhines and his UW colleagues have found changes in the subpolar North Atlantic Ocean that some say could trigger a new ice age.

At the same time, UW oceanographer James Morison and his team are headed back up to the North Pole next week to continue their arctic research, which many believe provides solid evidence of what would appear to be an opposite conclusion -- global warming. Morison's team has found evidence of a thinning polar ice sheet.

What the heck's going on here?

In a word: gyres -- massive, cyclical currents in the ocean and atmosphere that create plenty of turbulence for scientists trying to get the straight story on the future of climate change.

http://seattlepi.nwsource.com/local/169398_arctic16.html