PASADENA, Calif. A heady gale of information from a new NASA satellite about which way the wind blows and how strongly over the worlds oceans could prove invaluable to those who ply the seven seas, scientists said.
Although sailing ships no longer move the worlds cargo, surface winds still play an important role in how quickly and safely goods in the global economy can be shipped from port to port.
A strong tailwind can trim crossing times by hours for mammoth container-laden cargo vessels, which translates into thousands of dollars in saved crew and fuel costs. And winds can kick up storms and heavy seas that can further delay, damage or destroy ships bobbing on the waves.
But until recently, the study of how surface winds behave has been a spotty science at best.
"Winds drive the oceans on all scales," said Michael Freilich, the principal investigator on the NASA satellite, called QuikScat. "Oceanographers have called for years for more accurate data products."
This month, NASA began releasing to the public data gleaned by QuikScat, which uses a high-frequency microwave radar instrument called SeaWinds to measure the speed and direction of near-surface winds over the vast majority of the worlds oceans.
The satellite, launched in June 1999, replaces the Japanese ADEOS-Midori, which carried an identical NASA wind-measuring instrument before prematurely losing power in June 1997.
For the most part, ship captains use a medley of sources for marine forecasts. For surface winds -- tied inextricably to waves, storms and currents -- they have traditionally relied on sometimes-dicey measurements made by other ships and buoys.
"Those are just single-point measurements," said Paul Chang, a scientist at the National Oceanic and Atmospheric Administrations National Environmental Satellite Data and Information Service. "With QuikScat, you can see a complete picture right away."
QuikScat makes about 400,000 calibrated measurements a day, far more than the estimated 3,000 ship reports of surface meteorological measurements that flow in on a voluntary basis, said Freilich, an oceanographer at Oregon State University. Those measurements can be turned around and made available almost in real time about three hours after the satellite collects them.
Furthermore, Freilich said, ship-generated data are confined for the most part to the Northern Hemisphere or to very narrow shipping lanes. QuikScat covers about 90 percent of the globe each day at a resolution of 16 miles (25 kilometers).
"Ship routing tends to avoid the most severe conditions, so you assume the overall conditions are generally benign," Freilich said.
Although weather watchers can use QuikScat data independently, it will be most valuable once it becomes plugged in on a regular basis to more complex forecast models. Those models meld information on everything from clouds to temperature to atmospheric pressure. The more global and uniform that information, the better the forecast, experts said.
"If we dont have accurate measurements in a part of the ocean where a storm is developing, we cant make any analysis. And of course the more accurate the analysis is, the more accurate the forecast is," said Bob Cohen, the manager for meteorology and oceanography in the Sunnyvale, California office of Weathernews Inc.
At any given time, Weathernews provides weather forecasts to some 1,000 ships at sea around the world. (It also supplies weather data to various websites, including
advertisement
