Featured Research

from universities, journals, and other organizations

Clues to climate cycles dug from South Pole snow pit

Date:
February 25, 2013
Source:
University of California - San Diego
Summary:
Particles from the upper atmosphere trapped in a deep pile of Antarctic snow hold clear chemical traces of global meteorological events, climate scientists from France have found. Anomalies in oxygen found in sulfate particles coincide with several episodes of the world-wide disruption of weather known as El Nino and can be distinguished from similar signals left by the eruption of huge volcanoes, the team reports.

The chemical signature of global El Niño events opens a window to reconstructing paleoclimate cycles.
Credit: Image courtesy of University of California - San Diego

Particles from the upper atmosphere trapped in a deep pile of Antarctic snow hold clear chemical traces of global meteorological events, a team from the University of California, San Diego and a colleague from France have found.

Related Articles


Anomalies in oxygen found in sulfate particles coincide with several episodes of the world-wide disruption of weather known as El Niño and can be distinguished from similar signals left by the eruption of huge volcanoes, the team reports in the early online edition of the Proceedings of the National Academy of Sciences published the week of February 25.

"Our ability to link of reliable chemical signatures to well-known events will make it possible to reconstruct similar short-term fluctuations in atmospheric conditions from the paleohistory preserved in polar ice," said Mark Thiemens, Dean of the Division of Physical Sciences and professor of chemistry and biochemistry, who directed the research and dug up much of the snow.

Thiemens, graduate student Justin McCabe and colleague Joel Savarino of Laboratoire de Glaciologie et Géophysique de l'Environnment in Grenoble, France, excavated a pit 6 meters deep in the snow near the South Pole, with shovels.

"At an elevation of 10,000 feet and 55 degrees below zero, this was quite a task," Thiemens said. Their efforts exposed a 22 year record of snowfall, a pileup of individual flakes, some of which crystallized around particles of sulfate that formed in the tropics.

Atmospheric sulfates form when sulfur dioxide -- one sulfur and two oxygen molecules -- mixes with air and gains two more oxygen molecules. This can happen a number of different ways, some of which favor the addition of variant forms of oxygen, or isotopes, with and extra neutron or two, previous work by Thiemens's group has shown.

Unlike polar ice, which compresses months of precipitation so tightly that resolution is measured in years, relatively fluffy snow allowed the team to resolve this record of atmospheric chemistry on a much finer scale.

"That was key," said Robina Shaheen, a project scientist in Thiemen's research group who led the chemical analysis. "This record was every six months. That high resolution made it clear we can trace a seasonal event such as ENSO."

ENSO, the El Niño Southern Oscillation, is a complex global phenomenon that begins when trade winds falter allowing piled up in the tropical western Pacific to slosh toward South America in a warm stream that alters marine life crashing fisheries off Peru and Chile, and disrupts patterns of rainfall leaving parts of the planet drenched and others parched.

The warmed air above the sea surface lifts sulfur dioxide high into the stratosphere, where it's oxidized by ozone, which imparts a distinctly different, anomalous pattern of oxygen variants to the resulting sulfate particles.

In the Antarctic snow samples, the chemists found traces of these oxygen anomalies in sulfates trapped within layers of snow that fell during strong El Niño seasons.

Volcanoes too can shoot sulfur compounds high into the atmosphere where they react with ozone to produce sulfates with oxygen anomalies. Three large volcanoes, El Chichón, Pinatubo and Cerro Hudson, erupted over the course of this time sample, which stretched from 1980 to 2002 and encompassed three ENSO events as well.


Story Source:

The above story is based on materials provided by University of California - San Diego. Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Chakraborty, T. L. Jackson, M. Ahmed, M. H. Thiemens. Sulfur isotopic fractionation in vacuum UV photodissociation of hydrogen sulfide and its potential relevance to meteorite analysis. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1213150110

Cite This Page:

University of California - San Diego. "Clues to climate cycles dug from South Pole snow pit." ScienceDaily. ScienceDaily, 25 February 2013. <www.sciencedaily.com/releases/2013/02/130225153126.htm>.
University of California - San Diego. (2013, February 25). Clues to climate cycles dug from South Pole snow pit. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2013/02/130225153126.htm
University of California - San Diego. "Clues to climate cycles dug from South Pole snow pit." ScienceDaily. www.sciencedaily.com/releases/2013/02/130225153126.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) — Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) — A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) — The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins