A team of Spanish researchers has made a high-speed recording of elves and sprites in storms, fleeting and luminous electric phenomena produced in the upper layers of the atmosphere. Their analysis of these observations has been published in the Journal of Geophysical Research.
"This is the first time in Europe that we have been able to use high-speed video to detect transitory luminous phenomena taking place in the upper atmosphere – so-called sprites (in the form of a carrot or column) and elves (which are ring shaped)", Joan Montanyà, co-author of the study and a researcher at the Department of Electric Energy at the Polytechnic University of Catalonia (UPC), tells SINC.
The results have been published in the Journal of Geophysical Research and show there are many fewer elves in storms that form over land than those at sea, where electric currents apparently have greater energy, especially in winter. Some of the recordings show elves and sprites at the same time, evidence of the strength of lightning over the sea during winter storms.
This graphic shows the outlines of the elves (elves), elves (sprites) and blue jets of storms.
The scientists also observed the interaction between two sprites. A branch of one of them hit and bounced off the second, giving clues about their dynamics and electric structure. Sprites normally appear for around 40 milliseconds and 20 or 30 kilometres away from the site of the lightning.
"All these phenomena are related with storms, particularly winter storms, but they only appear in mesoscale convective systems (usually in large fronts), which produce lightning with high levels of energy or extreme electric currents", explains Montanyà.
As it is difficult to record these phenomena in situ during storms, the researchers placed a high-speed video camera on land with an image intensifier. This was used to remotely record a winter storm in the Western Mediterranean (at a distance of between 400 and 1,000 kilometres) between the coasts of Italy and Spain.
This series of images shows the clash of two elves captured at high speed during a storm in December 2009.
Credit: Montanyà et al.
The scientists also observed the interaction between two sprites. A branch of one of them hit and bounced off the second, giving clues about their dynamics and electric structure. Sprites normally appear for around 40 milliseconds and 20 or 30 kilometres away from the site of the lightning.
"All these phenomena are related with storms, particularly winter storms, but they only appear in mesoscale convective systems (usually in large fronts), which produce lightning with high levels of energy or extreme electric currents", explains Montanyà.
As it is difficult to record these phenomena in situ during storms, the researchers placed a high-speed video camera on land with an image intensifier. This was used to remotely record a winter storm in the Western Mediterranean (at a distance of between 400 and 1,000 kilometres) between the coasts of Italy and Spain.
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