Published on January 15th, 2012 | by Duncan Riley0
Polar Stratospheric Clouds Are Spectacular
Many people know of the spectacular Aurora Borealis, but there’s an another amazing site that occurs in extreme northern and southern climates when icy clouds form in the lower stratosphere: polar stratospheric clouds.
Polar stratospheric clouds, also known as nacreous clouds (or mother of pearl clouds due to their iridescence), are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 meters (50,000–80,000 ft).
Although they look spectacular, they aren’t so great for the environment as they are implicated in the formation of ozone holes. The clouds support chemical reactions that produce active chlorine which catalyzes ozone destruction, and remove gaseous nitric acid, perturbing nitrogen and chlorine cycles in a way which increases ozone destruction.
The are formed, ironically given their relationship to ice, when the stratosphere is very dry. The clouds receive sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn or after dusk.
The above picture was taken by Göran Strand, who took this picture last night from Östersund, Sweden, as featured on Spaceweather.com. We’ve included a gallery of the amazing polar stratospheric clouds as follows: