Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

And now December’s weather

19.10.2001


Will our winter be white?
© Photodisc


Meterologists look up for long-range forecasts.

Looking high into the atmosphere now might tell us whether we’re in for a white Christmas. Unusual stratospheric conditions herald changes in winter weather in the Northern Hemisphere up to two months later, say US researchers1.

The finding won’t let your weather forecaster warn you to wrap up warm two months hence, but it may be a valuable addition to meteorologists’ toolkits. "The effect works on average, but it doesn’t happen every time," says one of its discoverers, Mark Baldwin, of Northwest Research Associates in Bellevue, Washington.



It is currently almost impossible to forecast the weather more than a week in advance. "Everyone’s searching for predictive power on the timescale of 10 days to seasons," says Brian Hoskins, who studies atmospheric processes at the University of Reading, UK. "It looks as if, for Europe, the stratosphere could provide a bit of that power over a few weeks."

Baldwin is now working with meteorologists to factor his finding into their computer models of Europe’s climate. "Weather forecasters are aware of the effect, but they’re not yet using it," he says.

Aim high

The stratosphere begins about 10 kilometres above the ground, and extends to a height of about 50 kilometres. Conditions here generally change more slowly than they do lower in the atmosphere, but there are occasional large shifts in the patterns of air movement.

Baldwin and his colleague Timothy Dunkerton analysed daily satellite maps of a stratospheric air current called the Arctic Vortex. This blows westwards, with occasional reversals, around the top of the globe at 200-300 kilometres per hour.

They found a strong relationship between unusual wintertime conditions in the vortex and subsequent unusual weather in the Northern Hemisphere.

The vortex extends into the lower atmosphere, where it tends to trap cold air at the North Pole. If it weakens, the air can drift south, taking cold, snowy and windy conditions to Europe, Asia and North America. An abnormally strong vortex, in contrast, presages unseasonably mild weather.

Changes that are strong enough to cause weather blips "happen a little more than once a year", says Baldwin. He also believes that smaller stratospheric changes might affect the weather. The stratosphere could act like a sort of delayed mirror, reflecting changes in the lower atmosphere back down several months later.

The Arctic Vortex is felt through the Arctic and North Atlantic oscillations. These surface air-pressure features strongly influence the Northern Hemisphere’s winter climate. So predictions made using Baldwin and Dunkerton’s model would work best for western Europe.

The correlation between the stratosphere and the lower atmosphere isn’t in doubt, says Tim Palmer of the European Centre for Medium-Range Weather Forecasts, also in Reading. But he is sceptical as to whether there is a physical link between the two layers. Stratospheric air is so thin, he says, that it’s hard to see how it could influence the denser air below.

It is important to answer the question one way or another, says Palmer, as meteorologists need to know whether to include more stratospheric information in their models and observations.


References
  1. Baldwin, M. P. & Dunkerton, T. J. Stratospheric harbingers of anomalous weather regimes. Science, 294, 581 - 584 , (2001).


JOHN WHITFIELD | Nature News Service
Further information:
http://www.nature.com/nsu/011025/011025-4.html
http://www.nature.com/nsu/

More articles from Earth Sciences:

nachricht NASA looks to solar eclipse to help understand Earth's energy system
21.07.2017 | NASA/Goddard Space Flight Center

nachricht Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>