Editor’s note: If you’ve ever been fascinated by storms or unique weather events, this one’s for you. When we interviewed Kent City senior Fernando Diaz-Guzman about his interest in meteorology, there were several weather phenomena he was excited to discuss. We asked if he’d be interested in writing something for our Student Voices section to describe and explain one of his favorite weather events to study, and he was happy to oblige. Read on to learn more about transient luminous events like red sprites, elves and blue jets.
By Fernando Diaz-Guzman, Kent City High School senior
Kent City — What is a transient luminous event?
It’s a name for a type of lightning event that can happen with thunderstorms or thunderclouds. To better understand where TLEs happen, first you need to understand the layers of the atmosphere where these events can be found.
There are five different layers of the atmosphere, all associated with varying ranges of height from the surface of the Earth:
- The troposphere (from the Earth’s surface up to 4 miles above the Earth), contains most of our weather events, bringing in thunderstorms, severe weather events, winter storms or windy days.
- The stratosphere (4-31 miles above the Earth) contains an important ozone layer that helps protect us from ultraviolet radiation.
- The mesosphere (31-53 miles up) contains most of our planet’s gases; it is a layer where meteors burn up and a meteor shower can be seen.
- The thermosphere (53-375 miles up) shares space with the ionosphere and usually has a climbing temperature. When objects pass through this layer toward Earth, they can reach up to 4,500 degrees Fahrenheit. Our satellites sit in this layer, rotating around Earth.
- The exosphere (375-6,200 miles up) is the outermost layer of Earth, there is not much to this layer as it is a space to separate Earth and space.
Transient luminous events such as red sprites, blue jets or elves can all be found in these layers of the atmosphere. They are fascinating to learn about, as they can happen with several thunderstorm events and produce positive or negative charged lightning. They are unique lightning events that we sometimes may not observe unless we look for them. The TLE events in thunderstorms usually are more likely to happen if they have more charge or energy above the thunderclouds in the atmosphere.
Red sprites are a type of lightning charge where the lightning strikes toward the ground. Red sprites can be spotted in thunderstorms above the active thunderstorm-charged cloud and appear as a large but weak discharge, occurring nearly at the same time as a positive cloud-to-ground lightning strike. The sprites can be up to 60 miles from the cloud top, lasting up to a few seconds. They can appear scattered, like a jellyfish or bundle of carrots. They are visible at night most of the time, but can’t be seen by the naked eye as easily away from the thunderstorm. The best way to see them is to be away from a thunderstorm source and look up into the stratosphere or mesosphere.
Blue jets, sometimes called gigantic jets, occur above the top of the thundercloud with a height of 25-35 miles or higher, and can last a fraction of a second. They are not directly associated with cloud-to-ground lightning like the red sprites, but sometimes occur with negative charged lightning. They appear blue, either in a narrow shape or partially spread upward into the atmosphere, where pilots commonly observe them. You could potentially see this event if you are a passenger on an airplane away from the thunderstorms. Sometimes the height of the blue jets can go into the stratosphere or, rarely, into the ionosphere.
Elves, another of these unique weather events, are disk-shaped horizontal glowing areas that can be up to 300 miles wide, lasting nearly 1/1000th of a second. They are found way above the areas of active cloud-to-ground lightning, usually in the ionosphere or thermosphere, and are associated with energetic electromagnetic pulses extending up into the ionosphere. Elves were first discovered in 1992 with a low-light video capture by a space shuttle. This event is nearly impossible to observe with the naked eye, but can be observed with satellites.
