Noctilucent clouds forming at the edge of space may be associated with the warming of the planet.
The sky over Antarctica lit up with electrically blue seasonal silver clouds, which arrived much earlier than they should.
Noctilucent clouds (or “night light” in Latin) are made of tiny ice crystals that form near the edge of space about 50 miles above the Earth’s surface. They can be seen in the summer twilight at 50-70 degrees north or south of the equatorial line (it is summer in the southern hemisphere).
Scientists, using NASA's Aeronomical Ice Satellite (AIM), reported on the discovery of silvery clusters over the Antarctic on November 17, 2013, citing their early arrival.
The document was published in 2016 in the March issue of the journal “Geophysical research”. They suggest that clouds began to appear earlier due to climate change.
“The polar stratospheric winds of the southern hemisphere moved to the summer point quite early this year,” said AIM scientist Coral Randal from the University of Colorado. “But the early start of the season didn’t come as a surprise to us.” NASA says that noctilucent clouds form in the summertime due to winds and atmospheric humidity. More water molecules reach the upper layers of the atmosphere, which allows them to mix with pieces of meteoroids at the edge of space. In summer, when the temperature of the upper atmosphere cools down, ice crystals form.
“In recent years, noctilucent clouds have intensified and spread greatly. When they first appeared in the 19th century, it was necessary to go to the polar regions to see them. From the beginning of this century, they began to be noticed closer to the equator in Colorado and Utah, ”NASA said in a 2013 press release.
One reason may be a high concentration of greenhouse methane, which is oxidized due to a complex series of reactions and creates water vapor. So says AIM Leading Scholar James Russell from Hampton University.
A large volume of water vapor can grow ice crystals, which then form silvery clouds.