Antarctic snow inaccurate temperature archive

Feb 15, 2006
Antarctic snow inaccurate temperature archive
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.

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.

Source: NWO

Explore further: Dawn spacecraft captures best-ever view of dwarf planet

add to favorites email to friend print save as pdf

Related Stories

UNL drillers help make new Antarctic discoveries

Jan 21, 2015

Using a hot-water drill and an underwater robotic vehicle designed, built and operated by a University of Nebraska-Lincoln engineering team, scientists have made new discoveries about Antarctica's geology ...

Hotter, weirder: How climate has changed Earth

Dec 02, 2014

In the more than two decades since world leaders first got together to try to solve global warming, life on Earth has changed, not just the climate. It's gotten hotter, more polluted with heat-trapping gases, ...

Fountain of youth underlies Antarctic Mountains

Nov 19, 2014

Time ravages mountains, as it does people. Sharp features soften, and bodies grow shorter and rounder. But under the right conditions, some mountains refuse to age. In a new study, scientists explain why ...

Recommended for you

Dawn spacecraft captures best-ever view of dwarf planet

3 hours ago

NASA's Dawn spacecraft has returned the sharpest images ever seen of the dwarf planet Ceres. The images were taken 147,000 miles (237,000 kilometers) from Ceres on Jan. 25, and represent a new milestone for ...

Image: Striking lightning from space

7 hours ago

Lightning illuminates the area it strikes on Earth but the flash can be seen from space, too. This image was taken from 400 km above Earth in 2012 by an astronaut on the International Space Station travelling ...

Are asteroids the future of planetary science?

7 hours ago

I don't think I ever learned one of those little rhymes – My Very Educated Mother Just Served Us Nine Pizzas – to memorize the order of the planets, but if I had, it would've painted for me a minimalist ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.