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 balloon mission captures electric blue clouds
24.09.2018 | NASA/Goddard Space Flight Center

nachricht 558 million-year-old fat reveals earliest known animal
21.09.2018 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

Im Focus: New devices based on rust could reduce excess heat in computers

Physicists explore long-distance information transmission in antiferromagnetic iron oxide

Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.

Im Focus: Finding Nemo's genes

An international team of researchers has mapped Nemo's genome

An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

 
Latest News

Matter falling into a black hole at 30 percent of the speed of light

24.09.2018 | Physics and Astronomy

NASA balloon mission captures electric blue clouds

24.09.2018 | Earth Sciences

New way to target advanced breast cancers

24.09.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>