13 environmental scientists reach South Pole by tractor

Team trekked 800 miles, collecting samples of ice and air for climate study

January 07, 2003|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

A team of environmental scientists has arrived safely at the South Pole after an 800-mile overland trek slowed by unexpectedly deep snow and high winds.

The 10 men and three women, traveling in heated shelters towed by a pair of 13-ton tractors, were the first American-led party to make the overland traverse to the Pole since a U.S. Navy resupply mission in 1961.

In a telephone news conference yesterday, via satellite from the Scott-Amundsen South Pole Station, researchers with the fourth annual International Trans Antarctic Science Expedition (ITASE) said they gathered hundreds of ice cores and air samples along the way.

Analyses of the cores and other data should reveal how global climate change has affected Antarctic weather and glaciation over the past several hundred years, they said.

They also hope those changes will reveal something about the future of Antarctic ice sheets and global climate change.

"ITASE provides a missing link to the climatic data set for the last 100 years, and allows us to go back much farther in time than we could on any other place on the planet," said expedition leader Paul Mayewski, a glaciochemist from the University of Maine.

Members of the expedition - an international team working on behalf of scientists from 19 countries - began assembling in early November.

They were flown to the Byrd Surface Camp, about 450 miles inland from the West Antarctic coastline and 800 miles from the South Pole.

By contrast, the 1961 Navy expedition - also pulled by tractors - began on the coast at McMurdo Station, passing through Byrd Camp en route to the Pole.

The ITASE team set off from Byrd Camp on Nov. 23, towed by two 27,000-pound Caterpillar tractors. Each $250,000 tractor pulled three or four 5-ton sleds carrying the expedition's living quarters, fuel and supplies.

Team members lived and worked in heated, insulated, plywood modules 10 feet wide and 20 feet long.

One contained a kitchen and bunks for the three women. Another held bunks for the men and scientific stations for ice-penetrating radar, atmospheric chemistry and other experiments.

Unlike early explorers "on the ice," the ITASE team also enjoyed satellite guidance, satellite telephone communications and Internet connections with the outside world.

"We were perhaps, by comparison with being at home, not very comfortable," said Mayewski. "But we did travel in a fair amount of comfort."

Even so, less than two days out, the expedition bogged down when the tractors and sledges sank into unexpectedly deep, soft snow.

"We were very surprised at how much snow there was, and for the first time in four years we were having trouble pulling the load," Mayewski said.

They tried hitching both tractors together, to pull the sledges in tandem. But in the end they turned back to Byrd Camp and ordered wider tracks for one of the tractors and wider, more bouyant skis for the sledges.

On Dec. 7 they started out again, and this time they made better progress. The sled trains stopped eight times while team members drilled 450 ice cores up to 120 meters long. The 3-inch-thick cores were carefully labeled and packed for the trip back to the United States.

The scientists also sent tethered and untethered balloons aloft to gather data on atmospheric chemistry as high as 15 miles up.

"We continued to encounter very thick patches of snow," Mayewski said. "We also found that temperatures were extremely mild."

It was midsummer in Antarctica. But the low temperatures ranged from an unusually toasty minus-7 to minus-18 degrees Fahrenheit. That was well above the minus-20 and colder readings expedition planners had expected.

Warmer, snowier weather is just what climate models predict for western Antarctica during El Nino events such as the one now under way. (El Ninos occur when ocean surface temperatures in the eastern Pacific are unusually warm.)

Mayewski said ITASE ice cores should document hundreds of years of El Nino-influenced temperature and precipitation changes in Antarctica.

Studies of sea salt and sulfur compounds produced by marine organisms and blown onto the ice could reveal long-term changes in weather patterns over the oceans surrounding the continent. And other chemicals might document centuries of increasing air pollution from human activities.

The team also worked to provide "ground-truthing" data to test the accuracy of remote sensing by satellites of conditions in the region.

Extreme weather was a risk throughout the trip. At the second drilling site, a storm blew up. "We had had winds gusting at well over 40 mph and very thick blowing snow," said a University of Maine graduate student, Dan Dixon. "We could barely see 10 feet."

Team leaders ordered the sled trains turned into the wind to minimize the amount of snow that would pile up alongside the sleds.

When the storm ended, Dixon said, there was 4 feet of snow that had to be shoveled away from the sleds. "It wasn't too big a job," he said.

The ITASE traverse comes almost exactly 100 years after British explorer Robert F. Scott launched the first serious, but unsuccessful, attempt to reach the South Pole, in 1902.

Scott tried again in 1911 and reached the Pole in January 1912. But he lost the race to Norwegian explorer Roald Amundsen, who got there first, just a month earlier. Scott and his entire team died on the return trip when unusually bitter cold set in near the end of their journey.

The ITASE team pulled in to the NSF's Scott-Amundsen South Pole Station on Jan. 2, just 27 days after they left Byrd Camp for the second time.

Team members have already begun the return trip - by air. Their tractors and sleds will remain at the Pole until another traverse is planned, perhaps two years from now.

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