. Earth Science News .




.
WEATHER REPORT
Correlation between summer Arctic sea ice cover and winter weather in Central Europe
by Staff Writers
Potsdam, Germany (SPX) Feb 03, 2012

This graphic illustrates the amplified warming of air masses above the Arctic ocean. Starting with the lowest sea ice cover in September evolving to the following winter temperatures are increased in years with less sea ice cover notably in the lower troposphere. Black contoured areas are particularly significant. scaling of x-axis: temperature diffenrence (Celvin) between means of years with low sea ice (2000-2009) and high sea ice (1989-1999) concentrations. scaling of y-axis: hight in hPa as pressure coordinates. Graphic: Ralf Jaiser, Alfred Wegener Institute

Even if the current weather situation may seem to speak against it, the probability of cold winters with much snow in Central Europe rises when the Arctic is covered by less sea ice in summer.

Scientists of the Research Unit Potsdam of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association have decrypted a mechanism in which a shrinking summertime sea ice cover changes the air pressure zones in the Arctic atmosphere and impacts our European winter weather. These results of a global climate analysis were recently published in a study in the scientific journal Tellus A.

If there is a particularly large-scale melt of Arctic sea ice in summer, as observed in recent years, two important effects are intensified. Firstly, the retreat of the light ice surface reveals the darker ocean, causing it to warm up more in summer from the solar radiation (ice-albedo feedback mechanism). Secondly, the diminished ice cover can no longer prevent the heat stored in the ocean being released into the atmosphere (lid effect).

As a result of the decreased sea ice cover the air is warmed more greatly than it used to be particularly in autumn and winter because during this period the ocean is warmer than the atmosphere. "These higher temperatures can be proven by current measurements from the Arctic regions," reports Ralf Jaiser, lead author of the publication from the Research Unit Potsdam of the Alfred Wegener Institute.

The warming of the air near to the ground leads to rising movements and the atmosphere becomes less stable.

"We have analysed the complex non-linear processes behind this destabilisation and have shown how these altered conditions in the Arctic influence the typical circulation and air pressure patterns," explains Jaiser.

One of these patterns is the air pressure difference between the Arctic and mid-latitudes: the so-called Arctic oscillation with the Azores highs and Iceland lows known from the weather reports. If this difference is high, a strong westerly wind will result which in winter carries warm and humid Atlantic air masses right down to Europe. If the wind does not come, cold Arctic air can penetrate down through to Europe, as was the case in the last two winters.

Model calculations show that the air pressure difference with decreased sea ice cover in the Arctic summer is weakened in the following winter, enabling Arctic cold to push down to mid-latitudes.

Despite the low sea ice cover in summer 2011, a cold winter with much snow has so far not occurred here in Germany. Jaiser explains this as follows: "Many other factors naturally play a role in the complex climate system of our Earth which overlap in part. Our results explain the mechanisms of how regional changes in the Arctic sea ice cover have a global impact and their effects over a period from late summer to winter. Other mechanisms are linked, for example, with the snow cover in Siberia or tropical influences. The interactions between these influential factors will be the subject matter of future research work and therefore represent a factor of uncertainty in forecasts."

It is the aim of the Potsdam researchers to find and analyse further mechanisms and to correctly show the Earth's climate system with the help of these mechanisms in models.

"Our work contributes to reducing the existing uncertainties of the global climate model and developing more credible regional climate scenarios - an important foundation to enable people to adjust to the altered conditions," explains Prof. Dr. Klaus Dethloff, Head of the Atmospheric Circulation Section at the Research Unit Potsdam of the Alfred Wegener Institute.

Related Links
Alfred Wegener Institute for Polar and Marine Research
Weather News at TerraDaily.com




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries




.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



WEATHER REPORT
NASA Renames Earth-Observing Mission in Honor of Satellite Pioneer
Greenbelt, MD (SPX) Jan 30, 2012
NASA has renamed its newest Earth-observing satellite in honor of the late Verner E. Suomi, a meteorologist at the University of Wisconsin who is recognized widely as "the father of satellite meteorology." The announcement was made Jan. 24 at the annual meeting of the American Meteorological Society in New Orleans. NASA launched the National Polar-orbiting Operational Environmental Satelli ... read more


WEATHER REPORT
Debt crisis, earthquakes slam Munich Re 2011 profits

US Navy comes to rescue of Iranian fishing dhow

Radioactive water leak at Japan nuclear plant: report

Japan studies flora and fauna near Fukushima plant

WEATHER REPORT
Smart paint could revolutionize structural safety

Samsung condemns 'anti-Iran' ad featuring its tablet

Green light for Malaysia rare earths plant

Malaysia plant threatens China grip on rare earths

WEATHER REPORT
Are Nuisance Jellyfish Really Taking Over the World's Oceans?

China water project to begin operating in 2013: report

Giant creature found in ocean depths

Filmmaker sounds alarm over ocean of plastic

WEATHER REPORT
Russian drill approaching long-buried lake

Voyage to the most isolated base on Earth

Norway blocking China's access to Arctic

The Arctic is already suffering the effects of a dangerous climate change

WEATHER REPORT
Africa land grabs 'could cause conflicts'

Livestock, not Mongolian gazelles, drive foot-and-mouth disease outbreaks

Cattle outbreak hitting Paraguay exports

Biodiversity enhances ecosystems global drylands

WEATHER REPORT
Rising Australian floodwaters force mass evacuation

New Zealand quake toll officially put at 184: report

Australia flood crisis set to last days

UN makes new appeal for Philippine flood victims

WEATHER REPORT
New study shows millions risk losing lands in Africa

UN says 30,000 fled recent Sudan fighting

Mali instals new defence minister after Tuareg raids

Tuareg rebels take Mali town after army pullout

WEATHER REPORT
Scientists decode how the brain hears words

Scientists decode brain waves to eavesdrop on what we hear

Making memories last

A glass of milk a day could benefit your brain


.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement