Nacreous clouds illuminate the twilight sky | MNN


Nacreous clouds

Nacreous clouds over the NASA Radome, McMurdo Station, Antarctica. (Photograph: Alan Light/flickr)

Throughout the winter in far northern and southern climes — like Scandinavia, Iceland and Antarctica — the twilight sky sometimes affords a sight of deceptively staggering magnificence. You’ll have seen clouds tinged with rainbow edges earlier than, however nacreous clouds, often called polar stratospheric clouds, fill the heavens with vividly undulating iridescent colours which are singular of their magnificence.

However whereas they might create a firmament worthy of magic and unicorns, they’re really wreaking havoc on our environment.

Nacreous clouds type within the stratosphere, nicely above tropospheric clouds at 70,000 toes or above — twice as excessive as industrial planes fly — where the ozone layer resides. And sadly, these mother-of-pearl clouds are a significant factor within the creation of ozone holes within the Arctic and Antarctic.

Often it’s too dry within the stratosphere for clouds to type, however nacreous clouds and their combination of supercooled water, ice crystals and nitric acid are different. And due to their distinctive composition, they turn into the right associate for chemical reactions from human-produced chlorofluorocarbons (CFCs), ensuing within the launch of chlorine gasoline, which breaks down ozone.

So though they might be beautiful to take a look at, it’s protected to say that not all clouds have a silver lining. However since mankind has made a concentrated effort to reduce CFC emissions, finally nacreous clouds can be a factor of the previous. Till then, they are going to stay a factor of poignant but tragic magnificence.

Nacreous clouds

Nacreous clouds over Asker, Norway. (Photograph: Wikimedia Commons)

Polar clouds

Photograph: Florentin Moser/Wikimedia Commons

Nacreous clouds

Nacreous clouds over Gaellivare, Lapland, Sweden. (Photograph: Bildagentur Zoonar GmbH/Shutterstock)

polar stratospheric clouds

Nacreous clouds over Asker, Norway. (Photograph: Sondrekv/Wikimedia Commons)

Mother-of-pearl clouds

Nacreous clouds over “Roll Cage Mary,” McMurdo Station, Antarctica. (Photograph: Alan Light/flickr)

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