Photo credit - Mark R Schoeberl

Photo credit – Mark R Schoeberl

We’ve worked our way from the ground up to the wispy extremes of the high etage (over 20,000 feet.) From the puffy delights of fair weather cumulus all the way up to the enchanting veils of cirrostratus. So where do we go from here? Why, up, of course. Why stop at a mere 20,000 feet when we can carry on up to 50,000, or even 80,000 feet? That’s where today’s cloud, nacreous, lives.

Nacreous clouds are among the most beautiful, being iridescent and highly colorful. Unfortunately, the beauty comes with a barb. Nacreous clouds, also known as polar stratospheric clouds, are composed of nitric acid and sulfuric acid, along with water, and are implicated in depleting the ozone layer.

Photo credit - Martin Machala

Photo credit – Martin Machala

Photo credit - Deven Stross

Photo credit – Deven Stross

Given their composition, nacreous clouds form in the high atmosphere at very cold temperatures – below minus 78 Celsius. The requirement of very low temperature accounts for their prevalence in polar regions. The origin of the name – nacreous – comes from nacre, or mother of pearl, because they share a colorful iridescence.

There is never any precipitation from nacreous clouds.

Photo credit - Deven Stross

Photo credit – Deven Stross

Some of today’s pictures come from the website of Deven Stross, where he has posted some photographs he took in Antarctica. I highly recommend visiting his site.


About arjaybe

Jim has fought forest fires and controlled traffic in the air and on the sea. Now he writes stories.
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5 Responses to Nacreous

  1. Laird Smith says:

    What is the speculation for the future of the of the earth concerning the nacreous cloud formations?

    Deven Stross website is very interesting and well worth the look.

    • arjaybe says:

      I don’t think nacreous clouds are unnatural. Without the human-produced ozone depleting chemicals, I think nacreous clouds are just part of the system, rather than a threat.

      Stross kinda makes you want to go to Antarctica, doesn’t he?


  2. emmylgant says:

    OMG! How utterly magical!
    Yes, it does make me want to go to Antartica… sort of if I can get warm enough to enjoy the clouds.

  3. arjaybe says:

    Judging from Deven Stross’ pictures, it looks pretty cold down there.-)


  4. mixedupmeme says:

    Very beautiful pictures from that web site. After reading your info and seeing the pictures, I will not be looking at clouds in the same old way. I usually see them as: Are they going to give me shade or not.

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