Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Equatorial water belt slackens

07.02.2002


30 years of slowing Pacific circulation may have changed climate


Less carbon may have reached the atmosphere from the Pacific Ocean surface over the past two decades
© Noella Ballenger



A recent slowing in the circulation of Pacific Ocean waters could have raised Pacific sea surface temperatures. It may even mean that less carbon has reached the atmosphere from the ocean surface over the past two decades.

Across the Pacific, water circulates in two giant loops in the Northern and Southern Hemispheres. It flows from the subtropics to the tropics about at a depth of 100-400 metres, rises to the surface at the equator, and heads back towards the poles at the surface.


This circulation has changed since the 1970s, say Michael McPhaden of the Pacific Marine Environmental Laboratory, Seattle, Washington, and his colleague Dongxiao Zhang of the University of Washington in Seattle1. Thirty years down the line, the amount of subtropical water that reaches the equatorial Pacific sea surface has dropped by 25%.

It had already been noticed that the temperature of the sea surface at the equatorial Pacific has risen by 0.8 oC over the past 30 years. This had puzzled researchers, as cloudy skies in this area have become more frequent over the past 50 years, providing cooling shade. McPhaden and Zhang’s finding explains the warming: the supply of cool subtropical water has dropped.

Getting warmer

The warming that sluggish circulation has brought to the equatorial Pacific may have something to do with the shift in the mid-1970s towards stronger, longer and more frequent El Niño events, in which ocean temperatures and wind patterns fluctuate.

El Niño events cause erratic weather around the world, including droughts in Southeast Africa and floods in parts of South America. But the link between decade-long circulation changes and shifts in the three- to seven-year El Niño cycles needs further investigation.

Nor can connections to global warming be untangled yet. "The beauty of the study is that it works with observations. So we know that the slowing effect is real and not just speculation," says Richard Kleeman, of the Center for Atmosphere Ocean Science, New York.

But it is too early, he thinks, to decide whether - or indeed how - the new results might tie in with the changing climate. "It is a very complex system," he says.

One potential connection lies in the carbon cycle. "The tropical Pacific is the largest oceanic source of carbon dioxide to the atmosphere," McPhaden and Zhang point out. The slowing circulation implies that less of this greenhouse gas has reached the ocean surface over the past decade. So, in the short term, the slowing circulation has helped to keep global warming at bay.

References

  1. McPhaden, M. J. & Zhang, D. Slowdown of the meridional overturning circulation in the upper Pacific Ocean. Nature, 415, 603 - 3608, (2002).

HEIKE LANGENBERG | © Nature News Service
Further information:
http://www.nature.com/nsu/020204/020204-8.html

More articles from Earth Sciences:

nachricht Colorado River's connection with the ocean was a punctuated affair
16.11.2017 | University of Oregon

nachricht Researchers create largest, longest multiphysics earthquake simulation to date
14.11.2017 | Gauss Centre for Supercomputing

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>