Posted on 06/11/2019 1:57:56 PM PDT by ProtectOurFreedom
Over the next few weeks, mid-latitude observers might experience the best noctilucent cloud viewing of their lifetimes.
Observers over the northern half of the U.S. are reporting something they have never seen before — electric-blue noctilucent (night-shining) clouds. They are wispy in appearance, and continuously change shape. They can be seen when the sun is about 6 to 16 deg. below the horizon, so about 1 to 2 hours after sunset or before sunrise. During that time of night the sun is still shining on these clouds, but not on any normal weather-related clouds.
In the late spring every year, people at far northern latitudes have often seen these on clear or partly-cloudy evenings. But solar-minimum conditions, with few if any sunspots, are causing cooling in the extreme upper atmosphere 50 miles high where the lowest atmospheric temperatures are recorded, approaching -150 F. That altitude is above 99.999% of the air in the atmosphere.
The wispy and undulating appearance of the clouds is due to upward-propagating gravity (air density) waves that cause temperatures to rise and fall, and the clouds form in the colder portions of those waves. Ice grows on meteor dust particles, creating a (nearly) outer space version of cirrus clouds. Time lapse photography has been used to show how the clouds change shape as the gravity waves well up through the extremely cold upper mesosphere:
If you miss seeing them in the next several weeks, take heart — solar minimum conditions should persist until the next NLC season arrives, making the summer of 2020 a good viewing opportunity, too.
(Excerpt) Read more at drroyspencer.com ...
NOCTILUCENT...!
Wow, that’s a nice one.
Don't ask me what this has to do with that.
Nice...
Now pardon me while I run back and forth screaming, “Woe is me, woe is me!”
I am so going to paint that last one... beautiful!
Reminds me of an image from the movie Weird Science.
Noctilucent Cloud.......
Sounds like a name that Elizabeth Warren would want before she became Pocahontus?
Or maybe the name of a woman in Australia?
I was just getting ready to post something along those lines.
I’ll have to add it to my list.
I already crossed Northern Lights off the list about 2 years ago when I saw them very early in the morning about 90 minutes before sunrise.
I accept the figures in the article, but am bound to say, those clouds don’t LOOK to be 50 miles high. They look to be at about 10,000 feet in the photos. Very curious. Thanks for posting. Does anyone else have an opinion?
Noctilucent clouds are seeded by meteoroid smoke and have nothing to do with “climate”.
the reason they are blue is simply because they are taken during the ‘blue hour’ (the time of night where it’s about too dark for the eye to see- but plenty light for the camera to see light)
Blue hour photography:
it looks l ike it’s light enough to see with hte eye in those photos= but it’s not- we would just see a black sky and it owudl be too dark to see- our eyes would not see the blue in the sky at all- - the camera however is much much more sensitive to light- and makes it look like it’s still light out-
Isn’t that? I think it was taken in Denmark. I found it via the link http://spaceweathergallery.com/index.php?&starting_point=50&PHPSESSID=qkgsd846fc3umiem14p8rncc93
Note it does NOT say the clouds are 50 miles up. It says “But solar-minimum conditions, with few if any sunspots, are causing cooling in the extreme upper atmosphere 50 miles high where the lowest atmospheric temperatures are recorded, approaching -150 F. That altitude is above 99.999% of the air in the atmosphere.”
So somehow the solar minimum is causing upper atmosphere cooling which is affecting clouds down below. These appear to be cirrus clouds which are made of ice crystals. Cirrus clouds can form at any altitude between 16,500 ft and 45,000 ft.
Your interpretation was correct. That is amazing to think of clouds forming at that altitude.
Wikipedia says "They are the highest clouds in Earth's atmosphere, located in the mesosphere at altitudes of around 47 to 53 miles. They are too faint to be seen in daylight, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in Earth's shadow...Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon. No confirmed record of their observation exists before 1885.
"Data from the Aeronomy of Ice in the Mesosphere satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form. The sources of both the dust and the water vapor in the upper atmosphere are not known with certainty. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The moisture could be lifted through gaps in the tropopause, as well as forming from the reaction of methane with hydroxyl radicals in the stratosphere.
Spaceweather.com has all you want to know about this
Why, you don't like the blue???
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
