In Antarctica, scientists go with the floe.
The 80 tons of equipment on the ice floe include instruments to measure the sea, ice and air. The expedition's primary goal is to study heat exchange between the ocean and the atmosphere and how the intervening ice influences that exchange.
"One of the largest uncertainties affecting the accuracy of models predicting the greenhouse effect is the role played by the ocean's sea-ice cover," says expedition member Douglas Martinson, an oceanographer with Columbia University's Lamont-Doherty Geological Observatory in Palisades, N.Y. "There is a surprisingly delicate balance between the atmospher above the ice and the ocean below it. Consequently, relatively small changes in either atmosphere or ocean can lead to significant changes in the character of the Antarctic sea ice, which in turn can have a major impact on climate."
Scientists also hope to learn more about the formation and dispersal of Antarctic bottom water, another Weddell Sea phenomenon that significantly affects global climate. Dense and frigid, Antarctic bottom water from the Weddell Sea surges northward into the world's oceans, drifting along 1,000 meters or more below the sea surface. "Antarctic bottom water is the refrigerator that makes the world's oceans cold," says Lamont-Doherty oceanographer Arnold L. Gordon, coordinator of the expeditions's science programs.
Past measurements have indicated that bottom water in the southern Weddell is warmer than botom water in the northern Weddell. Gordon speculates that the western edge of the sea somehow alters the bottom water as it flows northward. "We're not going to understand the whole story about the formation of Antarctic bottom water until we investigate that western rim," he told SCIENCE NEWS.
Since the greenhouse effect could alter the amount of Antarctic bottom water supplied to the world's oceans, expedition researchers will also try to determine the rate at which bottom water leaves the Weddell. "We really need to know: Is the Artarctic spigot going to become stronger or weaker as the climate changes under the greenhouse warming scenario?" Gordon explains.
Because of the large amounts of equipment and the relatively small crew, experiments at Ice Station Weddell probably won't get into full swing until mid-March, Gordon says. However, with the station currently drifting northward at only 3 to 5 kilometers per day, the researchers shouldn't miss any important data, he adds. The expedition will end when the floe reaches warmer northern waters and begins to melt, sometime in June or July.
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|Date:||Feb 22, 1992|
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