by Surabhi Agarwal

Some days ago, I received this beautiful picture from David. He saw these lovely clouds appear high over Newcastle, UK, recently, at dawn and at dusk. I know a bit about the common clouds floating above us, some beautiful, some dark, some low and some white fluffy ones flying high, but nacreous ones had eluded my attention. So I decided to learn more about them for two reasons. First, to really know what they are and secondly, to impress my husband who at the moment is studying weather in his bid to get a pilot’s license. His new hobby!

Here is what I learnt. Nacreous clouds, also known as polar stratospheric clouds or mother-of-pearl clouds, are rare and form in or near the polar regions at extremely high altitudes, typically in the stratosphere, where temperatures plummet to frigid levels. What makes nacreous clouds particularly stunning is their vibrant iridescence, a result of sunlight scattering through tiny ice crystals within the cloud. The play of colors—ranging from pinks and purples to blues and greens creates a painting on the polar heavens of ethereal beauty.

The occurrence of nacreous clouds is often associated with the presence of polar stratospheric ozone depletion, making them an indirect indicator of environmental changes. As we explore the vast reaches of the cosmos, understanding Earth’s atmospheric processes becomes crucial in drawing parallels with other celestial bodies and expanding our comprehension of the broader universe.