South Dakota Tech News
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FOR IMMEDIATE RELEASE
July 9, 2004
Contact: Steve Buchholz, Public Information Manager, 394-6082
Dr. John Helsdon, Professor, Department of Atmospheric Sciences, 394-1987
Research Funding Illuminates Lightning
South Dakota Tech researchers have received $132,800 from the National Science Foundation to continue an investigation into lightning in thunderstorms.
Dr. John Helsdon, a professor in the Department of Atmospheric Sciences, Richard Farley, a research scientist in the department, and Megan Holm, a graduate research assistant and Atmospheric Sciences master’s degree student from Spearfish, are collaborating on the project. They are using three-dimensional storm models to investigate a class of severe thunderstorms that produces a high percentage of positive polarity cloud-to-ground lightning (the normal cloud-to-ground lightning polarity is negative). The models, in combination with various observations from a field project conducted in 2000 in Kansas, will be used to verify or refute certain scientific hypotheses that have been offered to explain this phenomenon.
The project also involves testing various charging mechanisms that involve the interaction between liquid drops and ice particles to better understand the fundamental physics of how thunderstorms become electrified. The researchers also will study the Maxwell current (the total of all electrical currents flowing in and around thunderstorms) to investigate hypothesized relationships between this current and the lightning flash rate.
“The processes involved in the electrification of thunderstorms and the production of lightning are a primary focus in the field of atmospheric electricity,” Helsdon said. “While man has marveled at the beauty and violence of thunderstorms, our understanding of how thunderstorms form and become electrified to the point of lightning is incomplete.”
Field projects have been conducted to try to improve this understanding, but data obtained from instrumentation used in such projects is of limited resolution. “Modeling is a means to generate a more complete picture of what is happening because the model produces a high-resolution, time-evolving picture of all the interacting processes taking place,” Helsdon said. “Having this more-complete picture allows for the more thorough testing of hypotheses that relate to thunderstorm electrification.”
The project runs through March 2006.
“This is basic research, an exploration for the sake of gaining knowledge and insight into a familiar natural phenomenon,” Helsdon said.
Helsdon and Farley have been working together in the modeling of thunderstorm electrification for more than 25 years at Tech. They have pioneered much of what is used today in such modeling efforts worldwide. This includes the first electrical model simulation of an observed storm, the development of the lightning scheme that is now used in several models around the world, the creation of an explicit model of nitric oxide production by lightning from the lightning scheme, and the first presentation of results concerning the modeled behavior of Maxwell currents.
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