PORTLAND – A Maine winter is nothing compared to the conditions endured by University of Maine scientists as they collect data in Antarctica.

Paul Mayewski and his colleagues make up the U.S. research team that is part of the International Trans Antarctic Scientific Expedition, a program formed in 1990 to collect ice cores and other environmental data. They are traveling to the South Pole on a sled train pulled by two tractors.

During a recent interview by satellite phone, Mayewski, the field leader for the U.S. team, described a recent snowstorm. The temperature had approached minus 22, with the wind chill around minus 60.

Snow that falls on Antarctica slowly compacts and turns to layers of ice, leaving behind a record of the chemicals that were in the atmosphere at the time.

After they drill cores out of the ice, scientists can search that record for clues about global climate change.

The expedition scientists aim to collect the most comprehensive set of environmental data ever for the continent.

“The ultimate goal of our program is to understand the last 200 to 500 years of climate change and change in the chemistry of the atmosphere over Antarctica,” Mayewski said, “and apply as much of that as we can to an understanding of those things for the Southern Hemisphere.”

Mayewski is a professor of geological sciences and the director of the Institute for Quaternary and Climate Studies at the University of Maine. He has led more than 35 scientific expeditions to the Antarctic, including explorations of uncharted areas.

The team also includes researchers from the University of Maine, the University of Washington, the University of Arizona and the Cold Regions Research and Engineering Lab in Hanover, N.H.

This is the fourth year scientists have traversed Antarctica for the program. Their efforts have already yielded some rewarding results, including determining the impact of volcanic activity and El Nino on climate change in the Southern Hemisphere.

“We discovered the first evidence of the Chernobyl nuclear accident in the Southern Hemisphere, which is a real indicator of how far pollutants can travel,” Mayewski said. “We discovered very strong links between the climate of the rest of the Earth, in particular the tropical Pacific, and Antarctica, which has told us a lot about how the climate system works.”

The U.S. researchers will be only the second group ever to travel over ice from the West Antarctic Ice Sheet to the South Pole, which they hope to reach Jan. 6.

The team stops every 60 miles or so to drill 3-inch-wide ice cores and perform scientific experiments. On “really good days,” Mayewski said, they travel at 5 to 6 mph.

It takes two to three days to drill a core that captures a 200-year climate record. The scientists are also drilling a series of shorter cores.