Warming Antarctic waters begin to cool

[sharon sanders]

Warming Antarctic waters begin to cool


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Researchers on Polarstern recover a mooring.
ALFRED WEGENER INSTITUTE FOR POLAR AND MARINE RESEARCH


Antarctica's deep ocean waters are getting colder after years of warming, say researchers who have just returned from a Southern Ocean voyage aboard the German research vessel Polarstern.
Samples from previous expeditions showed that water at a depth of 4,500 metres in the Weddell Sea warmed by a tenth of a degree Celsius between 1989 and 2005, although the warming trend may have begun earlier.....


http://www.nature.com/news/2008/080430//full/453015c.html

 

[Burnham Institute]

Re: Warming Antarctic waters begin to cool

The Alfred Wegener Institute for Polar and Marine Research

http://www.awi.de/en/institute/


"The Institute's research mission is to improve our understanding of ocean-ice-atmosphere interactions, the animal and plant kingdoms of the Arctic and Antarctic, and the evolution of the polar continents and seas. Given the major role played by these regions within the Earth's climate system, global change is a central focus of the research effort at AWI."

 

[Niko]

Re: Warming Antarctic waters begin to cool

**Snipped**

Another major article on temperature trends in the Antarctic has appeared in a recent issue of the Journal of Geophysical Research by a team of scientists from Ohio State University, the University of Illinois, and the Goddard Space Flight Center; the research was funded by the National Science Foundation Office of Polar Programs Glaciology Program. Monaghan et al. begin their lengthy (21 pages ? quite long for geophysics) article noting that a previous research team studying Antarctica examined ?station temperature records for the past 50 years and report statistically insignificant temperature fluctuations over continental Antarctica excluding the Antarctic Peninsula, with the exception of Amundsen-Scott South Pole Station, which cooled by -0.17 K decade-1 for 1958?2000.? That is correct ? despite all you have heard elsewhere on the subject, the South Pole has been cooling over the past half century. The previous research team also reported that any warming in Antarctica has slowed and the cooling has accelerated in the more recent three decades.

Full commentary here:
http://www.worldclimatereport.com/index.php/2008/02/27/antarctica-ain’t-cooperating/#more-312

 

[Snowy Owl]

Re: Warming Antarctic waters begin to cool

Larger Pacific Climate Event Helps Current La Nina Linger
April 21, 2008

PASADENA, Calif. ? Boosted by the influence of a larger climate event in the Pacific, one of the strongest La Ni?as in many years is slowly weakening but continues to blanket the Pacific Ocean near the equator, as shown by new sea-level height data collected by the U.S.-French Jason oceanographic satellite.

Click here to see the new image available online.

This La Ni?a, which has persisted for the past year, is indicated by the blue area in the center of the image along the equator. Blue indicates lower than normal sea level (cold water). The data were gathered in early April.

The image also shows that this La Ni?a is occurring within the context of a larger climate event, the early stages of a cool phase of the basin-wide Pacific Decadal Oscillation. The Pacific Decadal Oscillation is a long-term fluctuation of the Pacific Ocean that waxes and wanes between cool and warm phases approximately every five to 20 years. In the cool phase, higher than normal sea-surface heights caused by warm water form a horseshoe pattern that connects the north, west and southern Pacific, with cool water in the middle. During most of the 1980s and 1990s, the Pacific was locked in the oscillation's warm phase, during which these warm and cool regions are reversed. For an explanation of the Pacific Decadal Oscillation and its present state, see: http://jisao.washington.edu/pdo/ and http://www.esr.org/pdo_index.html .

A La Ni?a is essentially the opposite of an El Ni?o. During El Ni?o, trade winds weaken and warm water occupies the entire tropical Pacific Ocean. Heavy rains tied to the warm water move into the central Pacific Ocean and cause drought in Indonesia and Australia while altering the path of the atmospheric jet stream over North and South America. During La Ni?a, trade winds are stronger than normal. Cold water that usually sits along the coast of South America is pushed to the middle of the equatorial Pacific. A La Ni?a changes global weather patterns and is associated with less moisture in the air, and less rain along the coasts of North and South America.

?This multi-year Pacific Decadal Oscillation 'cool' trend can intensify La Ni?a or diminish El Ni?o impacts around the Pacific basin," said Bill Patzert, an oceanographer and climatologist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The persistence of this large-scale pattern tells us there is much more than an isolated La Ni?a occurring in the Pacific Ocean."

Sea surface temperature satellite data from the National Oceanic and Atmospheric Administration also clearly show a cool Pacific Decadal Oscillation pattern, as seen at: http://www.cdc.noaa.gov/map/images/sst/sst.anom.gif . The shift in the Pacific Decadal Oscillation, with its widespread Pacific Ocean temperature changes, will have significant implications for global climate. It can affect Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, marine ecosystems and global land temperature patterns.

?The comings and goings of El Ni?o, La Ni?a and the Pacific Decadal Oscillation are part of a longer, ongoing change in global climate,? said Josh Willis, a JPL oceanographer and climate scientist. Sea level rise and global warming due to increases in greenhouse gases can be strongly affected by large natural climate phenomenon such as the Pacific Decadal Oscillation and the El Nino-Southern Oscillation. ?In fact,? said Willis, ?these natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.?

Jason's follow-on mission, the Ocean Surface Topography Mission/Jason-2, is scheduled for launch this June and will extend to two decades the continuous data record of sea surface heights begun by Topex/Poseidon in 1992. JPL manages the U.S. portion of the Jason mission for NASA's Science Mission Directorate, Washington, D.C.

For more information on NASA's ocean surface topography missions, see: http://sealevel.jpl.nasa.gov/ ; or to view the latest Jason data, visit: http://sealevel.jpl.nasa.gov/science/jason1-quick-look/ .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

http://www.jpl.nasa.gov/news/news.cfm?release=2008-066