Watching the World's Weather

Satellite pictures of all the world's weather were made available to all the world last week--and at bargain rates. With about $32,000 worth of standard components, any country that is interested can put together a station capable of querying Tiros VIII, the newest weather watcher that the U.S. has fired into orbit.

Slow Reading. Earlier Tiros satellites stored their pictures on magnetic tape, then transmitted a large batch while passing over expensive installations at Fairbanks, Alaska, Point Mugu, Calif., and Wallops Island, Va. By the time the views from space were forwarded to the world's meteorologists by radio facsimile, they were often too late to help in the forecasts of local weather. But Tiros VIII carries a new type TV camera; its shutter opens for three-thousandths of a second, forming a photoelectric picture of about 1,000,000 square miles of earth. Instead of fading almost instantly like an ordinary TV picture, the shot lasts for 200 seconds while a scanning device "reads" it slowly, then transmits it promptly by radio. When the new Tiros comes over the horizon, a ground station operator tracks it with a spiral antenna. Down from the satellite comes a picture of the cloud pattern it has just passed over.

If the station is remote from other sources of weather information, the picture may bring the first news of the approach of a dangerous storm. About 40 such stations will be set up around the world by the U.S.; other countries --even Russia or Red China--are free to use Tiros if they want to.

Gleams in the Wind. Tiros VIII also carries the standard TV camera with which earlier weather satellites have scanned the earth's clouds. And starting back with Tiros I, launched in '1960, pictures made by that camera have worked on a major revolution in meteorology. Covering vast areas from 400 miles up. the eyes-in-space have reported varieties of cloud behavior that had never been observed before. They have detected unsuspected relations between the cloud patterns and the weather on the surface. They have spotted infant hurricanes when they were hardly more than gleams in the eyes of the wind.

Such triumphs are only the beginning, say satellite meteorologists. Future satellites will do even better. They will measure temperatures of the ground and the atmosphere. They will tell how dense the clouds are, and how high. They will show clouds on the dark side of the earth and measure changes of water vapor in the air. When all this new information is analyzed continuously by quick-thinking computers, meteorologists will at last be able to watch all the world's weather all the time.

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