While most are familiar with what a bolt of lightning below a thunderstorm looks like, the phenomena that occurs above a thunderstorm is less known and even less photographed. Referred to as jets, sprites, and ELVES, an often colorful, magical light show can be seen high above thunderstorms below.
Known by scientists as a “transient luminous event” or “TLE”, the phenomena is believed to be caused by electrically induced forms of luminous plasma well above a thunderstorm in the upper layers of the atmosphere.
Of the TLEs, the most common are sprites. Sprites appear as bright flashes of red light that occur well above a thunderstorm; within these bright red flashes, octopus-arm-like tendrils can appear below them, bringing a very unusual but brief illumination high in the sky. The first color image of a sprite was captured on an aircraft in 1994.
Another TLE is a blue jet, which appears as a bright blue column of light that jets above a thunderstorm. Scientists believe this phenomena is a component of tropospheric lightning and a type of cloud-to-air discharge that begins in a thunderstorm and travels up. Other TLEs like sprites aren’t connected with tropospheric lightning, but TLEs like blue jets are triggered by it. The first captured view of a blue jet was taken by the Space Shuttle in 1989.
Scientists believe blue jets are seen less frequently than sprites. And because they’re obscured by thunderstorms, clouds, and rain showers at the surface, the best place to spot them is from space. The European Space Agency (ESA) has deployed the Atmosphere-Space Interactions Monitor, known as ASIM for short, on the European Columbus module of the International Space Station (ISS). ASIM studies high-altitude electrical discharges in the stratosphere and mesosphere high above thunderstorms. Here, blue jets and sprites could be documented.
One location that was in the right place at the right time on Earth to capture this phenomena on video recently was Mauna Kea on Hawaii’s Big Island. Mauna Kea is the tallest volcanic mountain in Hawaii. In addition to featuring snow that attracts winter sports enthusiasts, the summit area is dotted by some of the most famous telescopes in the world. One telescope is Gemini North, the northern member of the International Gemini Observatory, which is part of the National Science Foundation’s NOIRLab. A “cloud cam” at the Gemini North site, at an elevation of roughly 13,800 feet, captured a red sprite and a blue jet at the same time over a distant thunderstorm. It’s extremely rare to capture such phenomena on camera on Earth and even more rare that both a sprite and a blue jet was captured at the same time.
Beyond blue jets and sprites, scientists also hope to capture more imagery of ELVES. Short for Emission of Light and Very low Frequency perturbations due to Electromagnetic pulse Sources , these are somewhat dim, flattened glowing discs that last not much longer than a millisecond above a thunderstorm. This phenomena occurs in the ionosphere roughly 60 miles above a thunderstorm. ELVES were first discovered in a Space Shuttle mission in 1990 during a Mesoscale Lightning Experiment. Scientists believe the light is generated when nitrogen molecules become excited due to electron collisions created by an electromagnetic pulse caused by a traditional bolt of lightning in a thunderstorm.
In this new field of understanding these new high-altitude electrical storms, scientists have labeled other TLEs as ghosts, gnomes, pixies, and trolls. A ghost is short for Green emissions from excited Oxygen in Sprite Top; they appear as faint, green glows that appear right after a red sprite forms; it only lasts for milliseconds. A ghost was first observed recently in 2019. A gnome is a small, brief spike of light that points up above a thunderstorm; this upward moving bolt only lasts a few microseconds. Little is known about them. Pixies are unusual, white luminous events that form over a thunderstorm. Not directly related to a bolt of lightning below the storm, scientists aren’t sure why or how they form; they’re less than 100 meters across and only last for 10-20 milliseconds. A troll is short for Transient Red Optical Luminous Lineaments; these appear after strong sprites and appear as red spots with faint tails, similar to a jet from a storm.