By DIANE HELDT
Staff Writer
Between the polar bears and the thinning ice, an Ames Laboratory scientist leaving Monday for a six-week stint on a polar icebreaker has a lot to watch out for.
Jim Liljegren, an Ames Lab atmospheric researcher, will leave Monday for his research mission on the Des Groseilliers, a Canadian icebreaker that was intentionally frozen into the ice in October as part of a 13-month mission to study the arctic's role in global climate change. Liljegren will be studying polar clouds and global warming during his stay. He expects to return on June 23.
The ship is about 400 miles north of Barrow, Alaska, where a research station is located, and it is drifting west with the ice pack, Liljegren said.
He has heard recently from project officials that the ice pack is drifting farther west than originally anticipated and that the ice is getting thinner than expected. In fact, one large container has already fallen through the ice, Liljegren said.
"The summer season there is called melt season so you expect the ice to get a bit thinner, but for some reason it's getting thinner than normal," he said. "It's not clear if this is a seasonal variation or a one-time event or an effect of global warming."
The thinning ice likely won't affect Liljegren's research, because he will be focused on what's happening in the sky and because all of his equipment has been moved aboard the ship.
The polar bear problem could be another story, however. Liljegren has received shotgun training in case of a polar bear attack.
"They seem to have attracted a bear to the ship," he said. "The same bear has been seen near the ship for several days now and they're trying to shoo him away. They'll have a helicopter drop soon so they're hoping that will scare him off."
The prospect of dodging bears and thinning ice doesn't diminish Liljegren's enthusiasm for the trip.
"Polar measurements like this haven't been taken since 1957 and a ship hasn't been frozen in the arctic ice for 100 years, so this is a once in a lifetime opportunity," he said. "It's a very rare experience so I'm trying to make the most of it."
Liljegren is one of many U.S. scientists who will spend a six-week rotation on the ship. The research being conducted on the ship is part of a five-year international project of the National Science Foundation, called the Surface Heat Budget of the Arctic Ocean (SHEBA). The project aims to provide scientists with a better understanding of polar climates and how global changes affect them, Liljegren said.
One participant in the SHEBA project is the Department of Energy's Atmospheric Radiation Measurement (ARM) program, a broad-based effort to develop better models for predicting the effect of clouds on the Earth's climate. Liljegren has been involved with ARM for six years.
Liljegren's area of specialty is measuring the amount of water vapor and liquid water in clouds. On the icebreaker, he will gather data about the nature, make-up and structure of polar clouds. Liljegren chose now to go on the ship because the sun is up 24 hours a day during the summer, making it easier for him to study the clouds.
The polar regions are seen as key areas in determining the possible effects of global warming, because they are highly sensitive, and a change would likely be noticed there first, Liljegren said.
Researchers hope the data from the experiment will provide some of the answers to questions surrounding global warming, he said. Current climate models aren't accurate enough to predict what might happen of the Earth's surface temperature grows warmer, and new information could shed light on that, Liljegren said. Clouds play a big role in climate models because they trap heat in the atmosphere as well as deflect energy from the sun, he said.
"I've already been looking at some of the data that has come back from the ship," he said. "I'm eager to be there while the data is collected to see it for real."
Publication date: May 8, 1998
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