Weather Whys; Lightning Suppression

This is weather-wise. Lightning is nature's own fireworks display. Its spectacular show has caused wonder and awe for ages. In modern times, digital electronics technology has made it possible to apply new scientific understanding of lightning to the meteorological study of the phenomenon. As a result, scientists now have the means to determine the ground's strike points of lightning and to measure important quantities, such as the relative amplitude of the peak currents and the number of component strikes in a flash. Devices called direction finders or DFs are deployed across the nation. Each one can detect a lightning flash within a certain distance and can determine the direction to the strike point to within a degree or so. That information, along with the known distance between the two DFs, enables the system to calculate the ground strike location using relatively simple trigonometry. Scientists at the State University of New York at Albany with support from the National

Science Foundation, NASA, the Electric Power Research Institute, the National Weather Service and others, have developed a national lightning location network that can show where lightning is striking at any instant, as well as where it has struck since the inception of the network. The dangers of lightning have prompted some scientists to investigate ways of suppressing the strikes. One technique that's been tried is to seed the thunderstorm cloud with tiny slivers of metal coated plastic known as chaff. The theory is that the slivers should produce a slow, steady electrical discharge called corona, and that should keep the electrical potential low enough to inhibit lightning. Scientists report mixed results with that method. And otherwise, our writer is Christine Harbour, edited by Brian Walkie. Our executive producer is Karen Hope. Weather wise is made possible by a grant from the National Science Foundation and is a service of the University of Oklahoma. I'm Drew Barlow.