Montshire Minute: Antarctica, part2

Originally aired during the week of December 4, 2000

Monday

The days are long, and everyone slathers on the sunscreen. We'll be outdoors for hours at a time, and we'll get plenty of exercise. That's right, this week we'll be winging our way south to . . . the Antarctica! Think of it - the South Pole! Penguins! Admiral Byrd's famous headquarters! The 24 hour sunrises, the . . . hey, you're not getting excited about this. You were thinking more along the lines of the Caribbean or Cancun? Well, OK, in that case we'll sit here by the fire and listen to the dispatches of someone else who is now journeying in this winter wonderland. That is Dr. Norbert Yankielun, of the Cold Regions Research Engineering Laboratory in Hanover. He is one of twelve members of the U.S. International Trans Antarctic Scientific Expedition. Their mission: to collect samples of ice that lie 60 meters deep in the frozen surface of the continent.

Tuesday

Right now, a twelve-member team is making its way across western Antarctica, collecting ice samples. Sounds like looking for cow pies in a barn, huh? But the U.S. International Trans Antarctic Scientific Expedition team must make its way along a 1200-mile route in harsh conditions, drilling holes about 60 meters deep, and collecting what they call "firn." This is not pure ice, but compressed layers of snow that have fallen over the last 200 years or so. Each of the long, circular cores they extract will be cut into 60 different sections. Each section is treated with care, since a lot of time, energy and money have gone into collecting it. The ice cores serve as a record of climate and temperature change for many, many years. Melting or damaging this ice would truly be a tragedy! So each meter-long ice core is bagged, sealed, numbered, and placed in a cardboard tube.

Wednesday

When scientists extract ice samples from the frozen Antarctic glacier, each section is carefully bagged, sealed, numbered, and placed inside a refrigerator. Wait a minute. A refrigerator? In the Antarctic? Bert Yankielun, one of the researchers who is currently helping to collect these samples, explains that the refrigerator protects the ice and keeps the samples at a constant temperature. There may be a lot of jostling and temperature change along the group's 1200-mile traverse. The research team plans to collect 8 different ice cores along the way, and each one takes about a day to extract. A complex series of travel arrangements, which includes use of refrigerated ships, transports the ice samples back to the U.S. There, scientists can look at each core centimeter by centimeter to examine their chemistry and stratigraphy (layering).

Thursday

Ice cores taken from Antarctica shows us a picture of earth's climate history. By looking for minute bits of volcanic ash in the ice column, we can accurately "date" the core because we know exactly when many volcanoes erupted over the last hundreds of years. The volcanic ash went up into the atmosphere, only to drift down and be captured in the surface of the snows in Antarctica, Greenland and elsewhere. More snow fell and covered this nearly invisible layer of ash. There it has lain undisturbed for hundreds of years - until researchers drill a core through it! It is sort of like reading tree rings. Indicators of climate - like air temperature, precipitation, and amount of solar radiation - can be revealed by ice cores. By looking at this record, scientists can detect natural cycles in global warming and cooling.

Friday

Take a close look at the top layer of fresh snow in the winter. You can often see individual snow crystals loosely piled. Even if nothing disturbs the snow, the flakes will lose their crystal structure and become granular. After a while, the snow compacts together and settles. Dig into a snowbank late in the winter with a shovel, and you might notice the snow has definite layers, each one representing a different snowstorm. It's sort of like a history of the winter snowfall! Now, imagine hundreds of years of snowfall packed and compressed into hard ice. Dr. Norbert Yankielun, of the Cold Regions Research Engineering Laboratory, in Hanover, is one of twelve members of the U.S. International Trans Antarctic Scientific Expedition that is now drilling into the Antarctic ice sheet to "harvest" ice core samples. In the laboratory, scientists can detect natural cycles in global warming and cooling.