Automated Weather Stations Relay Data Via Cosmic Dust

At midnight, a computer in Boise makes a wake-up call to Galena summit.

The radio message bounces off a gaseous meteor trail and finds an unmanned weather-monitoring site at the summit. A reply is sent with a burst of weather data: maximum, minimum and average temperatures; snowfall; amount of water in the snow; and total accumulations of precipitation to date. Then the Boise computer tells the remote site to go back to sleep.

The whole exchange takes less than 50 milliseconds, or five one-hundredths of a second, said Bill Patterson, an electrical technician for the National Resources Conservation Service.

Similar conversations go on throughout the night as computers in Boise and Ogden, Utah, collect weather data from about 600 automated weather stations in 10 Western states, including about 75 sites in Idaho.

The automated data-gathering is relied on by people such as Gale Roberts, a soil conservation officer on high-water watch in his Hailey, Idaho, office. The weather network lets officials monitor precipitation and estimate runoff from mountain watersheds.

“More than 70 percent of the West’s water starts out as mountain snow,” Roberts said. “Farmers, hydroelectric power engineers, outdoor enthusiasts need to know how much water is in the snowpack.”

Roberts’ concern is 11 remote weather stations in the Big and Little Wood River basins. “They used to take the attitude of ‘fill and spill’ flood control, but with these remote sites, data are more readily available and flood control can begin earlier in the winter,” Roberts said.

Until about 20 years ago, most data was collected once a month. Information was collected using skis, snow machines and helicopters.

“Then it was decided that the data needed to be collected in a more timely fashion,” Roberts said.

The weather stations typically are placed in small meadows in the higher reaches of watersheds. Many are accessible only by helicopter.

Each site has a flat steel “pillow” filled with nontoxic antifreeze. As snowfall accumulates, the snow’s weight pushes the antifreeze up a plastic tube, allowing measurement. Meanwhile, gauges and recorders measure temperature and wind.

Atop an antenna tower, a small solar panel provides the site’s power.

The meteor-burst communication technique is made possible by a constant shower of sand-grain-sized meteors. The meteors burn when they reach the Earth’s atmosphere, leaving a gaseous trail capable of reflecting a radio signal.

Because billions of tons of cosmic dust fall to the Earth each year, a signal is assured of randomly finding a short-lived trail for a quick ricochet.