Stratospheric clouds, North Pole Observers report about the outbreak of the sighting around the Arctic circle. “On 13 February. The sky was filled with their bright colors from sunrise to sunset,” says MIA Stalnacke. Remembering polar stratospheric clouds at Kiruna, Sweden. These unusual clouds were also observed throughout Finland, according to Matti Helin photographed the phenomenon.
These clouds, which are sometimes called night-shining clouds are the highest clouds of the Earth.
It’s a very cold, very sparse and filled with tiny ice crystals clouds hovering at the altitude of about 80 kilometers above the surface of our planet. When the sun rays pass through these ice crystals, clouds are becoming a rich glowing blue color, clearly visible in a deep twilight.
What’s going on up there?
PSCs are a sign of very cold temperatures in the stratosphere. The clouds are made of ice. Indeed, that is the source of their remarkable color: High-altitude sunlight shining through tiny ice particles ~10µm across produce a bright iridescent glow. For ice crystals to form in the very dry stratosphere, temperatures must drop to around -85º C.
Once thought to be mere curiosities, some PSCs are now known to be associated with the destruction of ozone. Indeed, an ozone hole formed over the UK in Feb. 2016 following an outbreak of ozone-destroying Type 1 PSCs.
To investigate these clouds further, Spaceweather.com and the students of Earth to Sky Calculus will travel to Abisko Sweden for a week in March 2017. We plan to launch a series of space weather balloons into the Arctic stratosphere, measuring temperature, air pressure, and ambient radiation. If PSCs are present, our sensors will pass directly through them, and our cameras can photograph the colorful clouds at point blank range.
Yet another sign of the coming magnetic pole reversal? Rare events like this doe seem to becoming more often seen.