AMES, Iowa -- Jim Liljegren, an atmospheric researcher at the U.S. Department of Energy’s (DOE) Ames Laboratory, may soon find out what it’s like to live on thin ice.
Liljegren will spend May 13-June 23 on the Des Groseilliers, a Canadian icebreaker that was frozen into the ice last September as part of a 13-month mission to study the arctic’s role in relation to global climate change. A variety of instruments are aboard the ship and on the surrounding ice. The ship is about 400 miles north of Barrow, Alaska, and is drifting west with the ice pack.
Liljegren said he heard recently from project officials that the ice pack is drifting further west than originally anticipated and that the ice is getting thinner than expected. "They’re hoping that they don’t lose any of the instruments," he says with a laugh.
But the news doesn’t diminish his enthusiasm for the trip.
"I’m eager to go because, as an experimentalist, it really helps to go to the field and actually be there as the data are collected so that you get a reality check rather than simply being an armchair commando," says Liljegren, who will be gathering data about polar clouds.
The research being conducted on the ship is a vital component of a five-year, international project known as the Surface Heat Budget of the Arctic Ocean (SHEBA), aimed at providing scientists with a better understanding of polar climates and how global change affects them. Among the SHEBA participants is the DOE’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.
For the past six years, Liljegren has been responsible for ARM’s microwave radiometers -- instruments that measure the amount of water vapor and liquid water in clouds. One of the ARM radiometers is on the ice pack to gather much-needed data about the nature of polar clouds.
"Polar clouds are considerably different from what you find at midlatitudes and aren’t anything like what you typically find in the tropics," Liljegren says. "Because of the remoteness of the arctic, the data on polar clouds has been extremely limited."
The polar regions are viewed as key areas in determining the possible effects of global warming. Because the poles are sensitive regions, the effects of global climate change are likely to be noticed there first.
"If the climate models don’t treat the processes near the arctic very well, then their estimate of the impact of global warming may be incorrect," he says.
Scientists who have equipment aboard the icebreaker and on the surrounding ice pack have been scheduled for rotating shifts there. Because Liljegren wanted to see the clouds his equipment is measuring, he chose to go during the late spring when the sun is up continuously.
Living in the arctic, even briefly, has its dangers. Liljegren has received shotgun training in case of a polar bear attack. "I don’t expect the bears to be a real concern, but I think the training is a ‘better-safe-than-sorry’ measure," he says.
Researchers hope data from the SHEBA experiment will help provide some of the answers to the questions surrounding global warming. Scientists say current climate models aren’t accurate enough to predict what might happen if the Earth’s surface temperature grows warmer. Clouds play a dual role in the climate models since they help trap heat in the atmosphere as well as deflecting energy from the sun.
"Cloud models are very complicated and very sophisticated, but all of that sophistication cannot be put into these large climate models, and the large models have somewhat oversimplified how clouds form and what effect clouds have on the radiative balance," he says. "My area of research is to try to improve that state of affairs."
One of Liljegren’s planned improvements is rewriting software to enable the radiometer to measure more quickly, thus improving coordination between the radiometers and ARM’s new cloud radars. He is also developing an algorithm that combines infrared measurements of cloud temperature with the microwave measurements in order to determine the liquid water content of clouds more accurately than the current algorithm, which uses microwave measurements alone.
What excites Liljegren about climate research is the ability to look at how the ocean, atmosphere and land relate to each other. "Most of science seeks to break things down into finer and finer elements so that you understand the details of that element really, really well," he explains. "The focus in climate research is on the interactions among the different elements and how a change in one affects the others. You really get to see that the global climate system is just that -- a system."
Liljegren became involved with ARM while working at the Department of Energy’s Pacific Northwest National Laboratory in Washington, and in October moved to the Ames Laboratory.
Ames Laboratory is operated for the DOE by Iowa State University. The Lab conducts research into various areas of national concern, including energy resources, high-speed computer design, environmental cleanup and restoration, and the synthesis and study of new materials.
Release date: 4/22/98
Contacts: Jim Liljegren, (515) 294-8428; Susan Dieterle, (515) 294-1405
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Last revision: 5/4/98 sd