The stratosphere is a relatively clear layer of Earth’s atmosphere, almost always cloud-free.
But on July 25,2016, researchers at Argentina’s San Martín Base spotted a bank of fantastically colored clouds floating in the stratosphere above the Antarctic Peninsula.
As reported by the photographer, these are the biggest stratospheric clouds they’ve seen so far this year.
Those mysterious clouds are called “Polar Stratospheric Clouds”and form in the lower stratosphere when temperatures drop to around – 85º C (-121°F).
This explains why nacreous clouds are rare and where they normally appear. Even at the poles, such low temperatures are hard to achieve.
High-altitude sunlight shining through tiny (~10µm) ice particles in mother of pearl clouds produce bright iridescent colors by diffraction and interference.
Apparitions of these rainbow-colored clouds often persist for days, as some PSCs are now known to be associated with the destruction of ozone.
What a hallucinogenic spectacle to begin the day.
