Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antarctic snow inaccurate temperature archive

16.02.2006


According to Dutch researcher Michiel Helsen, annual and seasonal temperature fluctuations are not accurately recorded in the composition of the snow of Antarctica. His research into the isotopic composition of the Antarctic snow has exposed the complexity of climate reconstructions.



Polar ice caps contain valuable information about the earth’s climate. Helsen investigated the extent to which meteorological data are stored in the composition of snow in order to improve the interpretation of deep ice cores from the Antarctic ice cap. He demonstrated that annual temperature variations in Antarctica could not be accurately reconstructed from ice core investigations. The conditions during snowfall are not representative enough for the average weather over an entire year.

His research also revealed that although temperature differences over the entire continent of Antarctica have a major influence on the composition of the snow, there are strong spatial variations in this. Accordingly a simple conversion of the fluctuations in the snow composition to changes in the local temperature is unreliable.


’Heavy’ or ’light’ snow?

During climate reconstructions researchers mainly examine variations in the weight of the water molecules in the ice, the so-called isotope values. Differences in the isotopic composition of precipitation occur as a result of condensation cycles during atmospheric transport: heavier water molecules are precipitated earlier than lighter ones. Atmospheric temperature plays a major role in this process. Helsen simulated this process using recent meteorological data. With this the researcher demonstrated that although temperature differences across Antarctica could largely explain the observed variations in the isotope values, the spatial correlation between temperature and isotope value varies strongly from place to place.

The prevailing conditions during snowfall determine the climate signal that is stored in the snow pack. However a heavy snow storm is a relatively rare occurrence in the interior of Antarctica because the kilometres-thick ice functions as a barrier for depressions carrying snow. Therefore the conditions during snowfall are not representative for the annual average weather conditions. Only averages over several years will provide reliable climate data from ice cores.

Helsen emphasises the complexity of isotope variations in the hydrological cycle, even in a relatively stable area such as Antarctica. He therefore advises fellow climatologists to be careful when quantifying climate signals over a period of several years on the basis of ice-core data.

The data from several automatic weather stations which the Institute for Marine and Atmospheric Research Utrecht (IMAU) has maintained in Antarctica for many years were particularly valuable for the research.

Michiel Helsen’s research was funded by NWO.

Michiel Helsen | alfa
Further information:
http://www.nwo.nl/nwohome.nsf/pages/NWOA_6LJDZU_Eng

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>