DISCUSSION: Earlier this month, it was discovered that the Geostationary Lightning Mapper (GLM) on the GOES-East satellite had captured some of the first satellite imagery of a phenomenon known as gigantic jet lightning. But what exactly is gigantic jet lightning and how did the GLM “see” it?
Gigantic jets are a type of upper atmospheric lightning, also known as transient luminous events (TLEs). While most TLEs lack many of the characteristics of the lightning we usually see in thunderstorms, gigantic jets are different in that they are connected to the electrical discharges that cause “typical” lightning. In a thunderstorm, a build-up of electrical charges within the cloud leads to the formation of lightning. While the exact mechanism behind this build up of charges is debatable, what is known is that when enough charge is built up, energy is released from the cloud in the form of lightning. Normally we think of lightning as flashes within or between clouds, or as strikes between the cloud and the ground. With gigantic jets, the electrical discharge exits from the top of the cloud into the ionosphere, reaching upwards of 50 miles into the atmosphere. Gigantic jets have been captured in videos and photography for years, but it was only recently that they have been captured on satellite imagery. The GLM on the GOES-East satellite continuously maps and detects lightning over the Americas and surrounding oceans. Lightning strikes and flashes emit light through the top of the cloud, which is detected by GLM and shown in satellite imagery. Since gigantic jets are electrical discharges emitted through the tops of clouds, they too would be detected by the GLM. Furthermore, they would show up even brighter and more intense on satellite imagery than typical lightning flashes, since what is being detected in this case is the electrical discharge itself rather than just the light from the flash emitted through the cloud. Satellite imagery provided by the GLM can be used to help us further understand gigantic jets and other lightning phenomenon. To learn more about other neat observational stories both directly and indirectly related to atmospheric science, be sure to click here! ©2018 Meteorologist Stephanie Edwards
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