Lightning is just one of the many spectacular luminous events that occur in Earth’s atmosphere. A particularly sought-after and mysterious one is red sprites, flashes of red-orange light that happen at altitudes of 50 to 90 kilometers (31 to 56 miles). They are very difficult to capture as despite being huge – up to 40 kilometers (25 miles) across – they only flash for a millisecond or so, so it truly blows our mind that two astrophotographers have captured over 100 in a row dancing in the sky over the Himalayas.
Red sprites are electrical phenomena happening in the mesosphere. The color is caused by electric charges interacting with nitrogen, and the interaction creates the plumes and tendrils that we can see. Beautiful images of them can’t prepare you for the excitement of seeing them in action. This incredible video taken by astrophotographers Angel An and Shuchang Dong is stunning but it is also extremely valuable in helping us understand how these events come to be.
The duo captured a lot more than just sprites. From the observation site near Pumoyongcuo Lake in the southern Tibetan Plateau, the astrophotographers snapped dancing sprites, secondary jets, and the first-ever recorded case in Asia of a green airglow known as ghost sprites.
“This event was truly remarkable,” co-author of the new study on these “cosmic fireworks”, Professor Gaopeng Lu from the University of Science and Technology of China, said in a statement. “By analyzing the parent lightning discharges, we discovered that the sprites were triggered by high-peak current positive cloud-to-ground lightning strikes within a massive mesoscale convective system. This suggests that thunderstorms in the Himalayan region have the potential to produce some of the most complex and intense upper-atmospheric electrical discharges on Earth.”
The team of scientists had a challenge though. The video is great but lacks precise enough timestamps to study the sprites and related phenomena in the wider atmospheric context. So they had to find a way to better estimate the timings.
They did so by matching the video times to the location of the star field and then synchronizing it to satellite trajectories to get the exact occurrence times. As timekeeping goes it’s certainly an unorthodox approach but it provided what was needed to understand where the sprites came from. Lighting discharges from precipitations associated with a convective complex are to blame. The complex extends from the Ganges Plains in India all the way to the Tibetan Plateau.
The event has the highest recorded number of sprites ever seen in South Asia, and it shows that the area can compete with the American plains and the offshore European storms in terms of transient luminous events.
The study is published in the journal Advances in Atmospheric Sciences.
