The Big Chill.
Pack your bags--for an entire year. Make sure to stow plenty of long underwear, parkas, and' life vests. You're setting sail to one of the most bitterly cold, remote stretches on Earth--the Arctic Ocean. Oh, and get ready to be chased by hungry polar bears, to brave bone-chilling winds, and to tread on ice so thin you could plunge into frigid waters at any moment. Sound like Club Med--or Club "Mad"?
In the fall of 1997, a team of "mad" scientists set out aboard the 98-meter- (322-foot) long ship Des Groseilliers, a Canadian Coast Guard icebreaker. They purposely rammed the ship into a vast Arctic ice floe (floating island of ice) about 644 kilometers (400 miles) north of Prudhoe Bay, Alaska (see map, p. 14).
They remained stuck in ice from October 2, 1997, through October 11, 1998, though ocean currents and winds nudged the ship 640 km (400 mi) from its original position. The journey included a Canadian Coast Guard crew, a rotating team of 170 scientists, and a network of research camps of huts and tents that scientists set up off ice. Their mission: to unlock the secrets behind three factors that make Arctic climate unique--ice, ocean, and atmosphere.
ARCTIC HITS HOME
Why study the Arctic in the first place? During winter, a permanent ice cap about the size of the continental U.S., 7.8 million square kilometers (3 million square miles), blankets the Arctic Ocean. In summer, the ice cap shrinks to about half that size. Remote as it may seem, the Arctic's freezing and melting are more closely tied to your life than you'd think, says Richard Moritz, director of the Arctic program SHEBA (Surface Heat Budget of the Arctic Ocean).
Even if you live in Florida, you may shiver from an Arctic deep freeze once in a while. Huge masses of dense, cold air from the Arctic pile up to form high-pressure systems, areas in which the weight of heavy air presses down on Earth. Arctic air sinks and flows toward the equator, to areas of lower air pressure. (Higher temperatures at the equator cause air molecules to spread out; thus, lower air pressure.)
Conversely, hot air from the equator rises and flows toward the poles, where much of the warm air escapes back into space--one reason the Arctic is so frigid. Brrrrrr! It's exactly this heat transfer between the equator and poles that helps form global winds and drives overall climate.
Now, scientists are concerned that rising temperatures in the Arctic could tamper with worldwide weather. Over the past three decades, they've detected a rise in average temperature of 1 or 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) in many regions of the Arctic. The warming may result from natural weather cycles, like El Nino (see SW 11/7/97), or from human activity like burning fossil fuels, which spew heat-trapping carbon dioxide into the atmosphere.
Recent satellite data shows that between 1978 and 1996, Arctic sea ice (frozen seawater that forms the ice cap) shrank at a rate of 2.9 percent per decade. White ice and snow help keep the Arctic frigid by reflecting light and heat out into space, a phenomenon called the albedo effect (see Hands-On, p. 15). But a melting Arctic ice cap exposes more and more of the dark ocean, which absorbs heat. So continual melting would heat up the Arctic and impact worldwide winds and weather. Depending on where you live, that could mean more violent storms, floods, or deadly droughts. "We urgently need to predict global weather more than ever," says Moritz. The Arctic is one vital piece in the puzzle of Earth's climate.
Before SHEBA set sail, no one had ever studied in detail the simultaneous long-term changes in the Arctic ice, ocean, and atmosphere. And the last time a scientific ship deliberately became stuck in the polar ice cap for a full year occurred in 1893. "We found a suitable ice floe and ran the ship deliberately into a thick piece of ice," Moritz recalls. "Because the season was changing, it didn't take long for the ice to freeze around us."
The ship served as dormitory, restaurant, communications center, power station, and sometimes a refuge from polar dangers. When hungry polar bears stalked the camp, crewmen fended them off by lighting flares or by driving noisy snowmobiles. "Every team on the ice had to carry walkie-talkies and a firearm," Moritz recalls. "Fortunately, no bears were shot."
Once the ship locked into the ice, the scientists set up more than 100 measurement sites, some with plywood huts and weather-proof tents, within a 5-km (3-mi) radius of the ship. "We'd walk to the nearby experiments and visit the more distant ones with sleds and snowmobiles," Moritz says.
Darkness was another challenge. Except for power provided by the ship, scientists had to work in total darkness because the North Pole is tilted away from the sun in winter. In winter, temperatures plummeted to -42 [degrees] C (-44 [degrees] F), and the ice was frozen solid. In spring and summer, temperatures rose to a "balmy" 1 [degrees] C (34 [degrees] F), and the ice began to crack and melt. "You could break through a thin crust of ice just walking around," says Moritz. As a precaution, scientists wore life vests, while small boats ferried them across goopy melt ponds (melted snow on top of ice), and a helicopter transported them to faraway research sites.
As planned, the data came pouring in. "We've seen it all," says Moritz. "Melting, freezing, heating, cooling, ice ridges, cracks, leads, melt ponds." To collect their data, the SHEBA scientists deployed a vast array of instruments, including high-flying weather balloons and an airship that measured air temperature and wind speed. Scientists drove pole-shaped devices into the ice pack to measure ice thickness, density, and temperature. Torpedo-shaped robotic vehicles "swam" in open water to measure sea temperature and salinity (saltiness).
One significant finding: Clouds create a huge difference in the amount of solar radiation striking Earth's surface. Like giant umbrellas, clouds reflect some of the sun's heat energy back to space. But they also trap heat beneath them, warming the planet surface.
SHEBA scientists used radar as well as a shipmounted green laser beam to sweep the Arctic sky and measure cloud particles. "To our surprise, there was a lot more liquid in Arctic clouds than we expected," says Moritz. Now climate modelers who need to predict weather know they have to reproduce part-ice, partwater clouds to simulate Arctic cloud cover in winter.
Another surprising finding: The ice was thinner than expected in some Arctic regions and the seawater below was warmer and less salty than predicted. Yet another surprising result was the amount of insulation provided by snow cover. The snow covering the ice acts like a thermal blanket, and insulates the warm ocean from cold air, like a thick wall in your house. Pockets of air trapped in the snow add to the insulating effect.
Last May, the ice floe surrounding the ship began to melt. By October, the ship broke free and set sail for Alaska. Now Moritz and his team of scientists have a huge job ahead of them. During the next three to four years, they'll crunch all their data and try to incorporate their findings into new and improved climate models.
Maybe next time, they'll ram their ship into a warm, Caribbean island instead.
HANDS-ON MELT IT!
White ice reflects sunlight and heat, keeping the Arctic frigidly cold, a phenomenon called the albedo effect. But what happens when the ice cracks, exposing the dark sea below? Experiment with different colored ice to find out!
WHAT YOU NEED:
ice-cube tray, water, blue and green food coloring, 9 plastic cups, freezer, measuring spoons, a watch, desk lamp or sunny windowsill
WHAT YOU DO:
1. Fill the tray compartments with two tablespoons of water. Use food coloring to dye three cubes blue and three cubes green. Leave the rest clear or "white." Place the tray in the freezer.
2. When cubes are frozen, remove one of each color and put the rest back in the freezer.
3. Place each cube in a separate cup. Place cups on a sunny windowsill or under a desk lamp.
4. Use measuring spoons to pour off liquid from each cube and measure how much it melts after 2 minutes, 4 minutes, etc.
5. Repeat the experiment with a second and then third set of ice cubes. Average your results.
Which colored cubes melted first? Last? Explain your results. What do you think happens to Arctic ice as more of the green-blue sea is exposed?
DON'T STOP NOW!
What color shirt should you wear to stay warm in winter and cool in summer? Why?
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|Title Annotation:||scientists embed ship in ice floe for a year|
|Date:||Feb 8, 1999|
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