Polar Stratospheric Clouds

Dec. 21, 2023

Recently, weather watchers have captured images of rare Polar stratospheric clouds over Scotland, northern England and the West Midland.

About Polar Stratospheric clouds (PSC):

  • These are also known as nacreous clouds or mother of pearl, due to their iridescence.
  • Formation:
    • These are formed in very cold conditions over Polar Regions and within the stratosphere, around 12-19 miles (19-31 km) high, far above our normal clouds.
    • These clouds are made of smaller ice particles than those that form more common clouds.
    • These small particles help to scatter light in a different way, which gives them their unique appearance
  • PSCs typically make their first appearance in January.
  • Impacts of these clouds
    • The frequency of these clouds is often a harbinger of ozone depletion, as they play a crucial role in stratospheric chemistry.
    • PSCs provide a surface for chemical reactions where benign forms of chlorine are converted into reactive, ozone-destroying forms.
    • They also remove nitrogen compounds that would otherwise moderate the destructive impact of chlorine on the ozone layer.