Aurora Borealis dune or the northern lights shaped like sand dunes already have scientific confirmation and interpretation. A team of 11 researchers and amateur scientists from Finland, Norway, the United Kingdom and the United States published this week in the journal Trade Predecessor AGU Study results confirm the conditions in the upper layers of the northern atmosphere that make dune-shaped aurora formation possible.
In addition to technical data, this article, first signed by Maxim Grandin, Professor in the Department of Physics at the University of Helsinki (Finland), emphasizes the importance of collaboration between citizen sciences, photographers and professional scientists.
In fact, the discovery or first observations of the aurora borealis now known as sand dunes dates back to January 2016 pictures taken by amateurs in the sky from Finland to Scotland.
Northern lights are seen in the shape of a sand dune in Laitila, Finland, in 2018, with the wave notched.
Initially, the videos and photos of these unique green wavy formations were archived along with hundreds of other equally attractive northern lights.
Except that the job of collecting pictures from the Facebook group Aurora Borealis alerts The book was published in 2018 Guide to the Aurora Borealis (The Northern Lights Guide), written by Mina Palmeroth, Johnny Josela, and Marcus Hotakinen, re-launching curiosity about the Aurora Borealis as sand dunes (see in Vanguard).
Thus, in January 2020, it was also published in Predecessor AGUThe first acknowledgment of this aurora form has yet to be documented.
Amateur photographers and seasoned researchers in Finland discover “dunes” – a new aurora in the northern sky pic.twitter.com/ByoGGTEQYb
TRT World Now (TRTWorldNow) January 29, 2020
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Sand dunes were seen [por primera vez, en 2016] For nearly four hours in a very large area, with a formation extending about 1500 kilometers from east to west and about 400 kilometers from north to south, “recalls postdoctoral researcher Maxime Grandin, of the University of Helsinki, in statements now made by this same university. .
The origin of the phenomenon
The northern lights are born when charged particles expelled by the sun, such as electrons, collide with oxygen and nitrogen molecules in the Earth’s atmosphere. Experts from the University of Finland recall that collision momentarily excites species in the atmosphere, and this excitement is released in the form of light.
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The new auroral shape called dune is relatively rare and strange in origin. “It appears that the differences in brightness within dune waves are due to the increased density of oxygen atoms in the atmosphere,” explains Professor Mina Palroth, co-author of the study now published in. Predecessor AGU.
In January 2020, the first hypothesis was made about the origin of this formation. The new type of auroral emission could be the result of oxygen concentrations in the atmosphere, in a rare emission wave that arises between the mesosphere (at the boundary of the atmospheric layer known as the atmosphere) and an inverse layer that forms intermittently below. This allows waves of a specific wavelength to travel long distances without fading.
The study published last May confirms data on the existence of electron deposition and temperature monitoring in the first hypothesis.
According to the new observational data, electron precipitation occurred in the area where the sand dunes appeared on January 20, 2016. Therefore, it is very likely that the electrons of sufficient energy were involved to produce auroral emissions at an altitude of about 100 km.
The observations were collected by the DMSP satellite’s SSUSI instrument, which measures, among other things, electron deposition, the authors of the new study explain.
Satellite data confirms that on the night of the main observation in 2016, there was an exceptionally strong temperature reflection layer in the atmosphere, or a barrier created by layers of air at different temperatures. The reflection layer associated with the wave channel origins was measured using a SABER instrument carried by the TIMED satellite. The observation supports the hypothesis that the auroral originates in regions of higher oxygen density occurring in the upper atmosphere waveguide, details the information released by the University of Helsinki.
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