Tree Treetops Sparkle with Ultraviolet Light During Thunderstorms
Thunderstorms can bring unexpected phenomena beyond just rain and thunder. Recent scientific studies reveal that during these storms, treetops can emit a sparkle of ultraviolet light, reminiscent of a Christmas tree adorned with lights, although invisible to the human eye.
This remarkable effect, long associated with the phenomenon known as Saint Elmo’s fire, occurs when electrical discharges produce a bluish glow from pointed objects, including ship masts, during storms. Recent inquiries have directed attention towards whether similar electrical discharges can occur at the tops of trees, a question that has now been answered through both laboratory and field observations.
Understanding the Science Behind the Glow
In a study published in the journal Geophysical Research Letters, researchers documented how the tips of trees release electrical charges, creating a faint blue and ultraviolet glow in response to atmospheric conditions during thunderstorms. Patrick McFarland, a meteorologist at Penn State, shared how this inquiry began during a casual lunch discussion with his advisor, William Brune. McFarland recalled, “He looked up at the tree and postulated, ‘Hmm, I wonder if those trees glow under thunderstorms.’”
The researchers decided to test this hypothesis in their lab, where they placed a branch on a high-voltage plate and created a negative charge in the air surrounding the branch. This experiment successfully produced the faint glow they were investigating, confirming that electrical discharges, known as coronae, could indeed be generated by tree branches.
Field Research: Capturing the Phenomenon
To investigate whether these electrical discharges could be observed in nature, the team converted a 2013 Toyota Sienna into a mobile weather station equipped with specialized instruments and a camera capable of detecting ultraviolet light. Their journey took them to Florida, known for its high frequency of thunderstorms due to the coastal breezes from the Atlantic Ocean and the Gulf of Mexico.
“We drove down to Florida for about a month,” McFarland explained. “You get thunderstorms almost every single day.” Although, the challenge lay not just in finding storms but also in locating suitable trees and setting up their equipment in public spaces.
Fortuitously, while returning to Pennsylvania, they encountered a thunderstorm in Pembroke, North Carolina. They quickly set up their equipment and recorded the electrical discharges from a sweetgum tree and a loblolly pine for 90 minutes, capturing 41 distinct coronae flashes, each lasting no longer than three seconds. Interestingly, these flashes did not remain stationary; they moved between leaves and branches, creating a twinkling effect akin to holiday lights.
Widespread Phenomenon
The observations from this North Carolina storm were corroborated by similar phenomena recorded in thunderstorms in both Florida and Pennsylvania, indicating that these electrical discharges are not isolated incidents. McFarland remarked, “These glows seem to be really, really widespread. There may be many, many more coronae occurring that we just don’t have the sensitivity to see.”
This research not only expands our understanding of atmospheric electricity but also raises questions about the ecological and environmental implications of these electrical phenomena, particularly in regions frequently affected by thunderstorms.
What’s Next for Research?
As scientists continue to explore the complexities of thunderstorm dynamics and their effects on local ecology, future research may focus on how these electrical discharges interact with other atmospheric phenomena and their potential impact on plant life and ecosystems. Understanding these interactions could provide valuable insights into atmospheric science and environmental management.
For those interested in the intricacies of weather patterns and their effects on nature, this research offers a fascinating glimpse into the unseen effects of thunderstorms and the electrical activities that accompany them.
We invite readers to share their thoughts on this captivating phenomenon and its implications in the comments below.
