(ORDO NEWS) — NASA’s AIM spacecraft discovered a silver cloud (NLC) inside the Arctic Circle – the first of the summer season of 2020.
The May 17 discovery marks one of the earliest seasons in the 14-year history of the spacecraft.
“In previous years, we saw the first NLCs appear between May 15 and May 27,” says Cora Randall, a member of the AIM science team at the University of Colorado.
“Only once, in 2013 (May 15), did the Northern season begin earlier than this.”
NLCs are the highest clouds of the Earth. Sown by meteoroids, they hover at the edge of space more than 80 km above the ground.
Clouds form when shreds of water vapor rise into the mesosphere in summer, allowing water to crystallize around spots of meteor smoke. Last summer, they spread far south to Los Angeles and Las Vegas, setting records for observations at low latitudes.
To find out why NLCs appeared so early this year, Lynn Harvey from the Colorado University’s Atmospheric and Space Physics Laboratory looked at data from NASA’s microwave sounder of limbs (MLS).
The following graphs show the humidity and temperature in the mesosphere over the past 14 years, since 2020 it is traced in red:
“Between May 1 and May 17, the conditions in the mesosphere have cooled significantly and moistened,” says Harvey, “so that 2020 became the second coldest and third wettest year in the history of observations”.
Silvery clouds were likened to a large “geophysical light bulb” because they turn on sharply, reaching almost full intensity over a period of no more than 5-10 days.
This means that a small blue cloud can soon expand and cover most of the Arctic.
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