Sunday, November 19, 2000

Exploring the plateau

Published in the Antarctic Sun

The U.S. segment of the International Trans-Antarctic Scientific Expedition left Thursday for Byrd Surface Camp to begin this season’s traverse of the West Antarctic ice sheet.

The project is a multi-national effort in which the U.S. component this year involves 10 research institutions and five areas of study: meteorology, surface glaciology, geophysics, remote sensing and ice coring.

“It’s five coordinated disciplines,” said Paul Mayewski, coordinator of the U.S. traverse group.

Last year was the first of this four-year project that will end at the Pole in 2003. The information the team collected last year is already helping improve scientists’ understanding of the world’s climate.

The data is specific to the region of West Antarctica where the traverse will occur, but it shows effects of regional and even global weather and climate systems.

“What we’re looking for isn’t just an understanding of Antarctica,” Mayewski said.

By looking at snow layers in Antarctica ice sheets revealing the last 200 to 500 years of the Earth’s climatic history, ITASE groups across the continent have already learned about the
relationship of certain Antarctic weather patterns to large-scale climate phenomena like El Niño.

“We already have seen some very interesting results,” Mayewski said.

The team is also comparing the results from their work in the Antarctic to similar work in the North Atlantic, another powerful element in the engine of Earth’s weather. While small changes are localized, Mayewski said, larger alterations are visible in ice cores from both ends of the globe.

This field season, the traverse team will cover 1,200 kilometers in a triangular path starting and ending at Byrd Surface Camp. During the drive, they will use downward-looking radar to map the strata in the ice beneath the route. They will also have a shorter range crevasse detector radar unit operating to keep the vehicles and researchers safe out on the plateau.

At roughly 100-kilometer intervals, they will stop for a few days to drill a 200-meter ice core. The core itself and the hole it leaves show the chemical and physical properties of the layers of
snow.

They will identify specific layers in the cores that can be cross-referenced to the radar data, allowing them to follow snow layers for hundreds of miles.

“It’s almost like a three-dimensional ice core,” Mayewski said.

The data they get from the cores and from the radar shows indicators of the extent of the sea ice, activity of marine life and duration of polar stratospheric clouds in recent centuries, Mayewski said.

This year the team will be able to haul more equipment and better shelters, because they have a Challenger instead of one of the two Tucker Sno-Cats they used last year. The other Sno-Cat will
continue the journey this season.

As the project progresses, Mayewski said, the setup and takedown at either end of the traverse will become more streamlined, as vehicles and supplies are left to spend the winter on the plateau.

“We should be able to go in with a very small amount of C-130 support,” Mayewski said. This is a big efficiency advantage, he said, as compared with individual field camps.

“There are 10 institutions that can potentially be served by two to three flights in and two to three flights out,” Mayewski said, adding that fuel airdrops will also be part of the support of
the field traverses. This year they expect to use seven flights in and four flights out.

To choose its exact route, the team uses satellite photos to avoid crevassed areas and other potentially problematic sites. But they also confirm satellite pictures by reporting on surface conditions and comparing that information to the pictures taken from space.

In addition to their own work and contributions to wider projects like the International Geosphere and Biosphere Project, one of this year’s shallow cores is at a possible deep-core site like the one at Siple Dome.

“This is a return of the 1960s style of science in this region, with 21st century technology,” Mayewski said.

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