South Pole Pioneers Find El Nino Climate Changes

By J.R. Pegg

WASHINGTON, DC, January 6, 2002 (ENS) - A U.S. research team that has just completed the first overland trek across Antarctica to the South Pole in 45 years believes its efforts will provide integral insights into the effects of El Nino and the overall workings of the global climate system.

The team, part of the International Trans-Antarctic Science Expedition (ITASE) program, traversed some 800 miles (1,200 km) from central West Antarctica to the South Pole. Along the way, the scientists drilled ice cores and perform a range of experiments all geared towards furthering the understanding of last 200 to 500 years of climate change and atmospheric change over Antarctica.

team

Part of the U.S. International Trans-Antarctic Scientific Expedition team at the ceremonial South Pole in early January. Paul Mayewski, the expedition leader, is in yellow coveralls at left. (Photos courtesy Daniel Dixon/National Science Foundation)
"The records we get from Antarctica tell us not only about what has happened in a continent that has been poorly understood, but one can throw the Southern Ocean into the same category," said U.S. ITASE principal investigator Paul Mayewski.

"We are able to monitor circulation systems and temperatures over the Southern Ocean in our ice cores. When you consider much of the Southern Hemisphere is made up of ocean, and Antarctica, ITASE really provides a tremendous missing link to the climate data set."

Mayewski, a professor of geological sciences and the director of the Institute for Quaternary and Climate Studies at the University of Maine, and several others from the 13 member team spoke to reporters today in the first live press conference in history broadcast from the South Pole.

This was the fourth Antarctic traverse for the U.S. ITASE program, which has collected some 2.5 kilometers (1.55 miles) of ice cores from Antarctica. Some 19 nations work with ITASE, which was formed in 1990.

The cold and relative isolation of Antarctica makes it an ideal location to study climate patterns, with the drilled ice cores providing clear records of climate change and atmospheric change.

"This allows us to go back much further in time than we can literally go anywhere else in the planet," Mayewski explained.

One of the team's goals was to gain a better understanding of El Nino, a disruption in the ocean-atmospheric system in the tropical Pacific. Scientific models predicted more snow in an El Nino year, something the research team experienced right away.

train

Front of a long train carrying the ITASE team's equipment and stores
The team, with two tractors pulling three or four large sleds piled with fuel, food and shelter, left Byrd Surface Camp on November 23, 2002, but the deep snow forced the team to return after only two days.

"We were very surprised how much more snow there was," Mayewski said.

After refitting the sleds to handle the heavier snow accumulation, the team departed on December 7, 2002, arriving at South Pole on January 2, 2003. On average, the team trekked some 60 miles a day, stopping to perform experiments and drill three inch and two inch ice cores.

The drilling of ice cores is only one of a host of other studies and experiments conducted by the team. These projects include surface glaciology programs that explored changes in accumulation rates, remote sensoring experiments that coordinated satellite imagery with ground observations, as well as a series of geophysics programs and atmospheric chemistry experiments.

"We've even been launching balloons into the atmosphere as high as 23 kilometers (14.3 miles) looking at changes in temperature and ozone, to see how they relate to the satellite pictures of ozone," Mayewski said.

"The U.S. ITASE program is penetrating down to bedrock in excess of three kilometers, going up into the atmosphere close to 23 kilometers, and covering spatially about 5,000 kilometers (3,107 miles) over the last few years using 11 integrated programs."

Temperatures throughout the trip were expected to fall well below -30 degrees Centigrade at sites close to the South Pole, but never fell below -28 degrees Centigrade.

"This was another indication of the effects of El Nino and a good demonstration that the model predictions for what might happen in West Antarctica during an El Nino are correct - it gets warmer and snowier," Mayewski said, adding that the ITASE data will further understanding of El Nino's effects.

In addition to El Nino, the ITASE researchers hope to provide further insights into the large low pressure field that surrounds Antarctica and the East Antarctic high pressure system. Between these two, Mayewski explained, there is the largest pressure difference that exists close to sea level on the surface of the planet.

The team also took data in search of chemical indicators that could tell them something about the stratospheric input into Antarctica. This could, Mayewski said, ultimately offer clues as to why over the past few decades East Antarctica has "actually been cooling, unlike much of the rest of the planet."

The researchers also hope the ITASE treks will provide increased insight into the melting of the West Antarctic Ice Sheet.

radar

The U.S. International Trans-Antarctic Scientific Expedition uses ice penetrating radar on the polar plateau.
In a study published yesterday in the journal "Science," a different group of scientists said the West Antarctic Ice Sheet has been melting at a rate of some two inches per year for thousands of years. If it continues at this rate, the 360,000 square mile (932,396 square kilometer) ice sheet will disappear in some 7,000 years.

This trend is likely to continue, according to the scientists who authored the study, and provides an important baseline for measuring additional melting caused by human influence on the climate. The recent thinning of the ice in West Antarctica contrasts with ice sheets in North America and Europe, which had nearly all melted 10,000 years ago when the melting in Antarctica began.

Mayewski said he is "very confident" the ITASE projects will help round out why the ice sheet is still melting and whether human behavior is a contributing factor. "We not only have ground based measurements that are allowing us to tell changes in ice thickness and accumulation and in floe properties, but we are now being able to link these with very detailed reconstructions of the surface topography," he said.

"It is a very big part of our program to try to not only understand natural climate, past climate and how it operates but to use that as a tool for understanding human impact in Antarctica and for making better predictions."

Mayewski expects it will take up to a year or more for the data to be analyzed and published.

For more information on ITASE, log on to: http://www.ume.maine.edu/USITASE/