↟ Mother of Pearls – Polar Stratospheric Clouds ↟

This phenomenon is something very rare occurring here in the Northern realms. The phenomenon is called ‘Mother of Pearls’, and can only form in winter under very specific conditions in the polar stratosphere at very high altitudes (up to 15 – 25 kilometers). They occur at extremely low temperatures, around -70°C to -90°C, which only happens a few times a year in the stratosphere over the Artic polar region.

Scientists claims that these are the highest, coldest and rarest clouds on Earth. They are most visible close to sunrise or sunset (civil twiligh) when the sun is between 1 and 6 degrees below the horizon. The sunbeams’ are making a prims effect through the ice crystals in the clouds, casting beautiful glowing pastel colors all over the sky.

These clouds comes in two variants: PSC1 and PSC2. Type 1 is dangerous to the ozone layer because they are composed of ice crystals and supercooled droplets of nitric acid and water. These clouds play a critical role in the depletion of the ozone layer by providing a surface of chemical reactions that release chlorine and bromine compounds, which destroy ozone molecules. The second type (PSC2) consists only of ice crystals which are not harmful and is specifically called ‘Mother of Pearls’. How to spot the difference? Type 2 is more angelic with strong colours, while type 1 is more dull and not that bright in colour.