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April 20, 2000
Huge ice masses break free and float away from Antarctica. Three hurricanes in two months wallop North Carolina. Record floods swallow Venezuela. Wherever you look, the weather seems to be getting more and more extreme. Scientists have traditionally tried to predict our worst weather cycles by studying the atmosphere, but they have yet to turn their full attention to the 70 per cent of our planets surface covered by water.
This summer will witness a sea change in climate forecasting, however, with the launch of an international project called Argo. Some 3,000 robotic floats will be cast adrift on oceans around the world in an attempt to monitor whats going on beneath the waves, so that scientists can better predict the earths climate months, or even years, in advance.
Why the ocean?
While it may seem that bad weather descends from above, in reality the atmosphere interacts with the ocean to create our climate. The oceans upper layers can store 1,000 times more heat than the atmosphere does, and are affected by subsurface conditions such as currents, temperature and salinity (the amount of salt).
For example, El Niño, the weather pattern that wreaks worldwide havoc every few years, starts with a warming of the upper layer of the tropical Pacific Ocean. By interacting with the atmosphere, this ocean warming can cause droughts, fires, floods and unusual storms in different parts of the world. Other ocean-atmosphere interactionssuch as the North Atlantic Oscillation, the Arctic Oscillation and the Pacific Decadal Oscillationare associated with climate change elsewhere around the globe.
While changes in the atmosphere happen quickly, the ocean moves at a much slower pace. So, by studying its fluctuations scientists hope to be able to better predict long-term climate conditions. "One of the crucial things that the Argo project is really providing is the oceanographic analogue for the weather balloons that meteorologists use to do the daily forecast," says oceanographer Breck Owens of the Woods Hole Oceanographic Institute, (WHOI) who is planning the first launch of a U.S. Argo float from Bermuda in July.
How will it work?
How Argo works
If you prefer to view it with Real Player, click here. clip produced by Tom Clarke; edited by Jed Boyar
Argo will eventually consist of a network of some 3,000 robotic floats spaced about 300 kilometers (186 miles) apart around the world. These floats will sink to a depth of about 2,000 meters (more than a mile) and drift with the ocean current for 10 days. Then theyll begin to rise, measuring temperature and salinity every 10 meters. Once they reach the surface, theyll send the data theyve collected to Argo scientists via an e-mail message that will be transmitted by satellite. Scientists hope to have the first 3,000 floats operational by 2005.
Within an hour researchers like Owens will be able to analyze the information. But it will also be immediately available on the Internet for anyone to view. "This data is actually a fundamentally different way of doing science," notes Owens. "Its a cultural change."
Its also a worldwide scientific effort. About half the floats will be launched by the U.S., while the other half will be launched by Japan, Canada, Australia and several European countries. Those that cant afford to build floats will be enlisted to help launch them. "Our goal is to be the Henry Ford of instruments," says Owens. The cost of the first array of floats is $36 million. The floats are expected to last for about 5 years and will be replaced at the rate of about 800 per year for what Owens hopes to be a long time.
What will Argo tell us?
Did You Know...
Climate refers to long-term weather conditions in an area, while weather refers to short-term local conditions like temperature, rainfall and humidity.
Ocean conditions will offer scientists clues about the climate that atmospheric conditions dont. For instance, by measuring salinity, researchers can discern changes in ocean currents and precipitation. They can then construct "weather maps" of the ocean that will be used in the computerized climate forecast models that predict seasonal events like El Niño. The data collected by the floats will also be used for short-term decisions such as where to steer ships and to construct ocean profiles that help scientists deduce climate conditions up to 100 years ago.
Lastly, the Argo program isnt just of interest to meteorologists and oceanographers. The U.S. Navy is footing part of the bill because knowing the temperature of the ocean is important for tracking submarines.