Weather Wars

Is Forecasting A Common Good, Or A Commodity?

- Andrew Blum

PAUL SAUER SPINS HIS HEAD LIKE A HAWK, STANDING ON THE ROOF OF the Marine Air Terminal at La Guardia Airport, as jets whine and fume on the tarmac below. “Pretty straightforward today,” he shouts. “A little stratocumulus to the north. A little bit of middle clouds, which is still moving through us to the south. And a little bit of cirrus above that.” He turns on his heels and heads back down to his office, one floor below. “The machine is not going to see that,” he says. “The machine—well, we’ll find out.”

Out on the runway, near the edge of taxiway DD, “the machine”—a ceilometer— sits on a small patch of grass, burnt to brown by jet exhaust. It measures cloud cover, but only directly above the airport. Even if the thickest fog bank were rolling in from the west, over Manhattan, the ceilometer wouldn’t register it until it arrived. That’s where Sauer comes in. La Guardia is one of 135 airports around the U.S. with a human weather observer, there to back up a suite of instruments known as an Automated Surface Observing System, or ASOS. Sauer watches the weather, and he watches these machines that watch the weather. Once each hour—more often, in poor conditions— he runs up to the roof, looks at the sky and then checks what he sees against what the machines have registered. With a few keystrokes at an old terminal, he changes the numbers. Rather than a single layer of scattered clouds at 8,000 ft., he sees three. “I did not accept the output from the automated system because it was not completely accurate,” he says. “I backed up the sky.”