A powerful lightning sprite that was visible from the International Space Station in 2014. (Image Credit: NASA/ESA)
Sometimes thunderstorms are so severe that they produce immense lightning strikes and intense thunderclaps that may keep you wide awake at night. Here’s a tidbit of information about lightning bolts that may shock you: some are so massive that they can spread over multiple states. By analyzing data from satellites and ground stations, scientists have discovered a lightning flash from 2017 that spanned over Texas, Oklahoma and Kansas, measuring over 500 kilometers. What’s impressive is that scientists also think that more discoveries of these flashes are likely to occur.
Mesoscale lightning was first discovered in the mid-1950s. However, it wasn’t until 1989, when sprites were first discovered, that the phenomenon started to gain more attention from meteorologists. Sprites are bright flashes that occur in clusters at an altitude of 50 to 90 kilometers above the Earth’s surface in mesoscale convective systems. 3D-Lightning Mapping Arrays (EMAs) have recorded sprites spreading through hundreds of kilometers in the sky. In one such occurrence in 2007, a sprite measuring 321 km in Oklahoma was recorded, which was declared a record-breaker by WMO (World Meteorologist Organization).
According to the study, authored by Walter Lyons and his team at FMA Research in Fort Collins, Colorado, the GOES 16/17 satellites contain a Geostationary Lightning Mapper (GLM) sensor with a near-uniform spatial resolution of approximately 10km that detects mesoscale lightning. On October 22nd, 2017, the GLM sensor detected “a lightning discharge that originated in northern Texas, propagated north-northeast across, Oklahoma, fortuitously traversed the Oklahoma LMA (OKLMA), and finally terminated in southeastern Kansas.” The data was gathered from the OKLMA, NLDN (National Lightning Detection Network) and the GLM. The new GLM sensors confirm that flashes that extend over 100 km are quite common.
GLM also uses algorithms that identify a single lightning flash. The algorithms only have about five seconds to detect every lightning flash across North and South America. The large amount of GLM data being transferred from the satellite can also cause it to become bogged down. To help solve this issue, algorithms stop when lightning flashes get too complex, causing single lightning flashes to be artificially split into multiple degraded flashes. Researchers applied a fix to the splitting issue and applied it to all the GLM data from 2018. The new data set allows researchers to study different types of lightning. The corrected data can also show how frequent lightning strikes and thunderstorms occur, document what flashes look like and to help locate extreme lightning across America.
Researchers expect these records to be broken in the future through encounters of larger lightning strikes. They have already discovered a 673-km lightning flash in the GLM data. These observations will also help scientists to understand how intense electrical events in the atmosphere occur.
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