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Posted on 09/25/2008 5:12:59 PM PDT by SunkenCiv
Noctilucent clouds, also known as night-shining clouds, were first described in 1885, two years after the massive eruption of Krakatoa, a volcanic island in Indonesia, sent up a plume of ash and debris up to 80 km into Earth's atmosphere. The eruption affected global climate and weather for years and may have produced the first noctilucent clouds.
The effects of Krakatoa eventually faded, but the unusual electric blue clouds remain, nestled into a thin layer of Earth's mesosphere, the upper atmosphere region where pressure is 10,000 times less than at sea level. The clouds, which are visible during the deep twilight, are most often observed during the summer months at latitudes from 50 to 70 degrees north and south -- although in recent years they have been seen as far south as Utah and Colorado. Noctilucent clouds are a summertime phenomenon because, curiously, the atmosphere at 85 km altitude is coldest in summer, promoting the formation of the ice grains that make up the clouds...
Twenty-five years ago, researchers at Poker Flat, Alaska, discovered that the clouds were highly reflective to radar... Bellan... now has an explanation: the ice grains in noctilucent clouds are coated with a thin film of metal, made of sodium and iron. The metal film causes radar waves to reflect off ripples in the cloud in a manner analogous to how X-rays reflect from a crystal lattice.
Sodium and iron atoms collect in the upper atmosphere after being blasted off incoming micrometeors...
Measurements of the density of sodium and iron atomic vapor layers show that the metal vapor is depleted by over 80 percent when noctilucent clouds are present.
(Excerpt) Read more at eurekalert.org ...
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I wonder if the HF guys operating in the 2-30 MHz band know about this. Looks like a good way to get long range comm on the cheap.
What’s the HTML code for your clever Google link?
Scientist Says Ice Meteors a Sign of Climate Change (Environut alert)
Reuters (Yahoo) | Fri Sep 27, 9:54 AM ET | Emma Ross-Thomas
Posted on 09/27/2002 9:06:27 AM PDT by narby
http://www.freerepublic.com/focus/news/758461/posts
Small Comets and Our Origins
University of Iowa | circa 1999 | Louis A. Frank
Posted on 10/19/2004 11:13:25 PM PDT by SunkenCiv
http://www.freerepublic.com/focus/f-bloggers/1250694/posts
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Cool :-). Thanks for the link.
Measurements of the density of sodium and iron atomic vapor layers show that the metal vapor is depleted by over 80 percent when noctilucent clouds are present.
Somehow, I suspect Rove is to blame.
Well, he *is* a magnificent bastard...
My pleasure.
That may be something that has been done by accident. :’)
Oh, I thought it was Bush’s fault.
Oh, I thought it was Bush’s fault.
Oh, no, no. This is HUGE. It smacks of “the architect...”
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