![]() The overall behaviour is consistent among individual years, making the observed seasonal cycle a robust general feature of TLE activity above Europe. mostly sprites, is shown to be largely consistent with lightning activity, with a 1/1000 of observed TLE-to-lightning ratio in regions with most observations. Red sprites are large but weak luminous flashes that appear directly above an active thunderstorm system and are coincident with. The two seasons peak, respectively, in August and November, separated by March and April with almost no TLEs, and a relative minimum around September. Characteristics of Thunderstorms and Lightning Flashes Which Produce Mesospheric Transient Luminous Events NTRS Authors: Walter A. The climatology shows intense TLE activity during summer over continental areas and in late autumn over coastal areas and sea. A Nikon D6 camera with a 50 mm lens was used, in a video mode of 60 frames per second. The majority of TLEs were classified as sprites, 641 elves, 280 halos, 70 upward lightning, 2 blue jets and 1 gigantic jet. The mission objective was to manually record lightning and transient luminous events from the Cupola window in the ISS, based on preliminary thunderstorm forecasts uploaded to the crew 24-36 hours in advance. The most common TLEs include red sprites, blue jets, and elves. They are rarely observed visually and not well understood. The number of TLEs per thunderstorm was found to follow a power law, with less than 10 TLEs for 801 thunderstorms and up to 195 TLEs above the most prolific one. Large thunderstorms are capable of producing other kinds of electrical phenomena called transient luminous events (TLEs) that occur high in the atmosphere. This is the first study to compare the meteorological background conditions for thunderstorms that produced gigantic jets in 48 nights against 83 reference cases with monitored thunderstorms that did not produce jets, using vertical profiles from ERA5 reanalysis near the event location. ![]() Because of this unprecedented number of European observations, it was possible to construct a climatology of 8394 TLEs observed above 1018 thunderstorm systems and study for the first time their distribution and seasonal cycle above Europe and parts of the Mediterranean Sea. In 2009 through 2013, the number of optical observations of TLEs reached a peak of 2000 per year. Since then, Eurosprite campaigns have been conducted to observe sprites and other transient luminous events (TLEs), expanding into a network covering large parts of Europe and coastal areas. In 1999, the first sprites were observed above European thunderstorms using sensitive cameras. Neubert, 2020: Climatology of transient luminous events and lightning observed above Europe and the Mediterranean Sea.
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