Trying to improve predictions of lightning strikes, a Tucson scientist has helped invent a new detector that operates on minimal power, enabling remote weather stations to be more effective.
Like other electric field meters, the device measures the strength of the electric field in the atmosphere, which determines the probability of lightning strikes occurring, said Leon Byerley, a Tucson lightning expert. Byerley teamed with University of Oklahoma meteorology professor William Beasley to invent the device.
Byerley and Beasley had to rethink how to make an electric field meter to design one that could operate on very low power, a goal that would make the device suitable for use at a remote weather station.
"We developed a number of techniques for reducing power consumption, for controlling the errors that are inherent in the measurements and for reducing the maintenance required on these instruments," Byerley said.
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The team built about 10 prototypes of the device and tested them at weather stations in Oklahoma.
"Some of the concepts were so appealing and so attractive we put it all together in a package," he said.
The university's technology development office searched out a manufacturer for the technology and found Campbell Scientific of Logan, Utah. Campbell pushed the ideas, adding enhancements along the way, to create a finished product in about five years. The Campbell Scientific C-S-110 Electric Field Meter has been on the market for almost two years, Byerley said.
Different versions of electric field meters have been in use for about 70 years, but historically have required a lot of electricity to function, Byerley said.
"The measurement this instrument makes is very difficult to make over a long period of time or without errors," he said. "We just couldn't do it five years ago, because the instruments on the market consumed quite a bit of power. It's so low in power now it's practical to put this instrument in the field with a solar cell and a battery, and operate it for a long period of time."
The device costs about $3,500, plus another $3,000 for a solar panel, battery and tripod, as the system is set up on the roof of a new National Weather Center building at OU.
Byerley said the strength of the electric field in the atmosphere on a typical sunny Tucson day is about 100 volts per meter, caused by the charge in the ionosphere inducing an equal and opposite charge in the atmosphere below. With the development of big cumulus clouds and looming thunderstorms, the atmosphere might read several thousand volts per meter.
Predictions of when lightning might occur are useful for the mining industry or when dealing with munitions or refueling, Byerley said. The NASA Kennedy Space Center in Florida has relied on electric field detection for decades.
Byerley said there are several dozen of the detection devices now operating around the world.
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