Study Maps the Pacific's Impact on Weather
For 10 years, an international team of scientists has examined how warm seas and the atmosphere interact to produce floods, drought
FARMERS around the world will benefit from a major atmospheric study recently completed here. The project will provide more-accurate information about when droughts, floods, or cyclones are coming - and how bad they will be.
The program, actually two together, is called TOGA COARE, which stands for the Tropical Ocean Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment. TOGA is a decade-long program to try to understand the El Nino sea-warming phenomenon by putting together data from weather stations and ocean stations over a wide area. The goal is to forecast droughts, floods, or stormy periods from months to years in advance. COARE is the specific four-month field-research component focused on the interaction bet ween the atmosphere and the water in the Pacific Ocean, which concluded its work last week.
While separate studies have been done in the sea and air in the past, this research is the first combined project.
The western Pacific warm pool, a huge expanse of tropical ocean along the equator northeast of Australia, plays a key role in climate variations. What happens here has an effect on weather all over the world.
The Western Tropical Pacific Southern Oscillation (South Americans call it El Nino) involves a warm event in the western region that causes a dry event or a change in circulation in the eastern region. The result is floods in parts of South America and drought across northern Australia.
"It's all a coupled system. Whenever one happens, the other happens, and the system covers two-thirds of the planet from the Indian Ocean across the Pacific, at least in the tropics," says David Carlson, who headed the international project office of TOGA COARE. "And we know it has effects on the North and South American continents and the Indian and Australian continents."
Central operations were at a Royal Australian Air Force base, but a more rugged research site existed at Honiara in the Solomon Islands, and ships and planes traversed the whole region. Research vessels from Australia, France, Japan, the People's Republic of China, South Korea, and the United States used instrumented buoys to measure temperature, salinity, and horizontal and vertical motion in the upper ocean. The US, Britain, and Australia supplied aircraft and pilots to fly missions from Townsville, Au stralia, the Solomon Islands, and Papua New Guinea to make measurements in the upper atmosphere.
Other countries that provided specialized instruments and satellites included Canada, the Federated States of Micronesia, Germany, Indonesia, Malaysia, Russia, Singapore, South Korea, Taiwan, and Nauru.
Some small island countries were concerned about floods caused by rising waters attributed to global warming. "On many of these atolls where the highest elevation is four meters, a meter's rise [in the ocean] looks like a drastic change," Mr. Carlson says.
Stuart Godfrey, the bearded leader of the Australian scientific vessel Franklin, which measured heat transfer between ocean and atmosphere, says the Australian government is keenly interested in furthering such research, since Australia just emerged from a three-year drought.
"When an El Nino occurs, this has a dramatic effect," says Mr. Godfrey. "The kind of understanding we hope to get will have more of an impact here than anywhere else."
The National Aeronautics and Space Administration (NASA) sent one of only three ER2 planes it has to do upper-atmosphere research. Pilot Jim Barrilleaux flew this pencil with wings in the upper 5 percent of the atmosphere for grueling eight-hour flights. In addition to flying the challenging plane, he also kept track of the scientific instruments on board that, among other things, put together a picture of what a cloud is composed of and what it's doing.
The data from TOGA COARE, says Carlson, can help farmers from Indonesia to Indiana better plan their crops.
"Indonesia would like to become an exporting nation in rice," Carlson says. "Should they shift over larger amounts of acreage? Should they develop new cultivated land? Invest more resources in long-term rice production? Because they're right in the path of the Southern Oscillation, they're intensely dependent on the El Nino and the rainfall and drought patterns that go along with that. Our ability to predict three years in advance what the average precipitation and average temperature over those years is
likely to be is very important."
Indiana, too, will benefit in the long run from the TOGA COARE data. "If you look at the precipitation patterns in the central US, they are tied in some way to what happens in the western Pacific," Carlson says. "About all we can say today is that when we get changes in the western Pacific warm pool, we get changes in temperature and precipitation in the central US. The goal is to tune the model so they can [forecast] that a crop-year in advance."
While the warm-water pool here has been recognized as an important influence on weather for the past 20 years, it hasn't gotten much attention.
"There were big data gaps, and hints from French oceanographic research cruises in the 1980s that there was something funny about the way the ocean worked here," says Carlson. "It had to do with the air-sea interaction. Finally, we had to do the air-sea-interaction experiment of the century, and we had to do it in this spot."
On that basis, the US National Oceanic and Atmospheric Administration (NOAA) started the 10-year TOGA project.
The last major global-atmosphere experiment was 20 years ago. And since then, computers have revolutionized the collection and transmission of data. Now data coming in from the project's planes, ships, and buoys can be seen in real time. A satellite network beams data to forecast centers and data sites around the world. In the future, global models may be turned into regional weather information.
From the start, TOGA COARE was planned internationally. It wasn't US-driven, although the US National Science Foundation supplied a large portion of the budget, and NOAA and NASA were also involved. COARE was managed by an international project office established in 1990 at the University Corporation for Atmospheric Research in Boulder, Colo.
Carlson says that, because each country is paying for its own participants, it's hard to estimate the total cost of the project. But he says the US has contributed about half the total cost, and it has spent $40 million.
The job of keeping harmony with all the different nationalities working here has fallen on Carlson's shoulders. "You can have all the best research equipment, planes, ships, but the limiting factor is the health and happiness of the people working for months in a difficult environment."
Despite four months of seven-day work weeks, and working straight through Thanksgiving, Christmas, and the US, Chinese, and Japanese New Years, he says, "It's been wildly successful."