Atop Mount Säntis, a rocky peak in the Swiss Alps, sits a telecommunications tower just over 400-feet tall that gets struck by lightning more than 100 times a year. The tower, which may experience its 1,000th lighting strike in 2019, might be the world’s most frequently struck object, reported IEEE Spectrum.
Now, researchers are installing a broadband interferometer instrument near the tower to better understand how lightning forms and to study its behaviors.
Mark Stanley of New Mexico Tech built the device complete with four antennas — three with bandwidth from 20 to 80 MHz to record powerful electromagnetic pulses in the very high-frequency range and one to measure sferics, which are low-frequency signals that result from the movement of charge.
“Basically, lightning is a giant spark,” Bill Rison, Stanley’s collaborator who teaches electrical engineering at New Mexico Tech told IEEE Spectrum. “Sparks give off radio waves, and the interferometer detects the radio waves.”
The antennas record lightning strikes in the clouds, collecting several gigabytes of data across the many separate pulses that occur within each flash. Those data can be made into a video that replays, microsecond by microsecond. The research team wants to identify what prompts lightning’s initiation or the familiar, audible “crack.”
The research could help inform the design of airplanes, electric grids and wind farms, plus industry safety. The team is studying upward lightning strikes recorded at the tower, which travel from ground-to-cloud instead of cloud-to-ground. Upward lightning often originates from tall buildings and structures, which can create a lightning bolt that shoots skyward, according to IEEE Spectrum.
“If we understand how lightning is initiated, we could take a big step forward on one of the other questions we’ve been trying to solve for a long time, and that’s to be able to predict lightning before it happens,” says Marcos Rubinstein, a telecommunications professor at Switzerland’s School of Business and Engineering Vaud and co-leader of the Säntis team.
July 17, 2019