Stratospheric Polar Clouds Above Northern Italy

Photographer: Paolo Bardelli  Summary Author: Paolo Bardelli 

Stratospheric polar clouds, as the name suggests, are typically confined to the poles and occur in winter at high latitudes where the stratosphere cools to temperatures of -120 F (-85 C), allowing them to form. Also called mother of pearl and nacreous clouds, they’re believed to be composed of nitric acid and traces of water vapor.

Exceptionally, on December 22, 2023, the temperature in the stratosphere above Europe was the lowest recorded in any December during the last 40 years. Stratospheric polar clouds were observed from northern Italy, where they put on a great show, which unfortunately I was unable to document. However, the next night, with the aid of moonlight, I was able to photograph these beautiful clouds at 2:00 a.m. (local time). See top photo.

On January 25, 2024, the mother of pearl clouds returned to our latitude, albeit in a less evident way as the stratosphere was not nearly as cold as in December (bottom photo). 

Photo Details: Top Photo - Canon 6D camera; Canon 28 mm lens; f/5.6; 1000 ISO.Bottom Photo - Canon 50D camera; Canon 28 mm lens; f/7.1, 30 second exposure; 400 ISO. Processing with PS CC.

Albusciago (Varese), Italy Coordinates: 45.7395, 8.7939Related Links:Nacreous Clouds over Norfolk, EnglandTypes of Clouds