What's the deal with noctilucent clouds appearing all over the place?

I love skywatching, and I often visit spaceweather.com to keep on top of what cool stuff is in the sky. Now, I know aurora are common with solar storms and I have a decent understanding on how they work, but what are these noctilucent clouds that are popping up all over the sky these past few months? Until this summer, I had never even heard of noctilucent clouds (NLCs).

After doing some preliminary research, it seems NLCs are rare but have been observed since the 1800's. Generally, they are more visible from space and on the ground they are usually just faint electric-blue whisps. That is, until this year....

This year the NLCs are getting so strong in the northern hemisphere that they are creating the illusion of dawn even in the middle of the night.

Quote from spaceweather.com site today:

On July 15th, a wave of intense noctilucent clouds (NLCs) descended over the continental United States. "They were so bright, I would have assumed the dawn was imminent, only it was an hour and a half before sunrise!" says Eve Wills, who sends this picture from Dillon, Montana.

It seems nobody knows exactly what causes this phenomenon, and I wanted to start this thread for some people that are more knowledgeable than me to chime in with their ideas. It seems odd that these are becoming so widespread (they have been seen in Europe for the past few months and are now appearing in North America) and so strong. They are also appearing at lower latitudes than ever:
(More quotage from spaceweather.com):

Similar reports have poured in from Colorado, Oregon, Washington, Nebraska, Idaho, the Dakotas and northern California. These sightings are significant because they come from places so far south. When noctilucent clouds first appeared in the late 19th century, they were confined to latitudes above 50o N (usually far above). The latitude of last night's Colorado sighting is only 39° N. No one knows why NLCs are expanding their range; it's one of many unanswered questions about the mysterious clouds.

So what gives? Is this an indication of some sort of Earth change or just something neat to check out this summer?

2009 NLC Gallery

interesting we have had cloud coverage like that here for the last few weeks especially before sunrise its surprising how bright they do appear to be. would be nice to know exactly what causes these

isn't it just because the sun is just under the horizon so that its high enough to light up the clouds but not enough to lighten the rest of the sky yet?

They are the highest clouds in the Earth's atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometers (47 to 53 mi). They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earth's shadow. Noctilucent clouds are not fully understood and are a recently discovered meteorological phenomenon; there is no evidence that they were observed before 1885.

en.wikipedia.org...

okay, so i was half right? lol
but then it leaves no explanation for why those types of clouds are being seen at such low latitudes, no?
is the upper atmosphere getting colder?

[edit on 7/16/2009 by double_frick]

reply to post by double_frick


Essentially, yes. The clouds are way up in the mesosphere (50mi up) where it is extremely dry so normally ice crystals are not able to form. Under the rare cases that crystals are able to form, then the clouds appear. They are so high up that the sun on the other side of the horizon reflects off of them thus they are visible at night.

The question is what is causing so much crystallization to occur way up there all of a sudden? And why is it happening at lower latitudes (farther from the poles) than ever before?

It is strange. Maybe that volcano in Russia from a few months ago? I'll have to see if these were appearing before or after that...

(I see we simulposted the same info.)

[edit on 16-7-2009 by nydsdan]

its not just the people at space weather that have noticed the, i either never saw it much before, or just never noticed them till i read about them, either way, scince i heard about them sometime last year ive seen loads of them, most nights this summer i have seen them.

Okay, does not seem related to the Russian volcano (Sarychev Peak) eruption. That happened June 12 and the NLCs were being seen earlier than that (at least June 4/5).

I read about the cause of this the other day but for the life of me I can't remember the source. From what I do remember it has something to do with the sun and some type of solar activity that is happening right now. In some areas people will be able to see the aurora borealis a lot further south than normal. Apparently this same solar activity can explain those types of clouds further south than normal too.

If I remember the source I will edit this and post the link here.

[edit on 16-7-2009 by QBSneak000]

When I was a child my grandfather used to call those clouds "mares tales". in the winter time it was seen by my grandfather as a precursor for snow/ice storms. In actuality, that may be true; however, it is an indication of ice particles in the clouds. With all of the "cooler than normal" temperatures throughout much of the US, it makes sense that these clouds would be observed more frequently.

en.wikipedia.org...

Just my 2-cents

This is a statement from spaceweather.com from 7-13-09

Noctilucent clouds almost always surge during years of solar minimum such as 2009. No one fully understands the link, but here is a popular idea: Low solar activity allows the upper atmosphere to cool, promoting the formation of tiny ice crystals that make up noctilucent clouds.

Here's the link.
www.spaceweather.com...

reply to post by sickofitall2012


Ah, good find! This solar minimum sure was a biggie I suppose!

I have a question for any cloud watchers and honeslty would like responses. Heres the deal: sunday morning i walked over to the store at 6 am and saw a beautiful array of clouds that were huge and tall and the tips were hit by the rising sun so that the tips were brilliant white. Ran back in to get girlfriend to see such a pretty morning sky and we both noticed the coulds directly above us looked like gray cotton balls in a pattern like crops or something, 4 or 5 rows with about 7 or 8 in each row and rows were lined up side by side. Heres the kicker: those cottonball clouds were out of focus, our eyes would water if we looked at those and was one the strangest illusions I have ever seen in the sky. Eventually they faded and changed shape like all clouds but the out of focus thing was very odd. Can anyone help me out here?


Posted Via ATS Mobile: m.abovetopsecret.com

reply to post by nydsdan


Yeah, what puzzles me is that if the atmosphere is so much colder, how does this play into the so-called global warming ?

Originally posted by sickofitall2012
reply to post by nydsdan

 

Yeah, what puzzles me is that if the atmosphere is so much colder, how does this play into the so-called global warming ?

The clouds were first seen above polar regions in 1885, suggesting they may have been caused by the eruption of Krakatoa two years before. But in recent years the clouds have spread to latitudes as low as 40°, while also growing in number and getting brighter. The reason for the clouds' spread is unclear, but some suspect it could be due to an increase in greenhouse gases. That's because the gases actually cause Earth's upper atmosphere to cool, and the clouds need cold temperatures to form.

Although the average number of noctilucent clouds has been increasing in recent decades, their abundance also seems to rise and fall with the sun's 11-year cycle of activity. The clouds thrive when the sun is quiet and spews less ultraviolet radiation, which can destroy water needed to form the clouds and can keep temperatures too high for ice particles to form.

Because the sun has been abnormally quiet in recent years, noctilucent clouds could be especially bright and numerous this summer in the Northern hemisphere. "We expect this year to be a bigger year because of lower solar activity," says Scott Bailey of Virginia Tech in Blacksburg, VA and a lead scientist for NASA's Aeronomy of Ice in the Mesosphere (AIM) spacecraft, which launched in 2007 to study the clouds. The clouds may be about twice as abundant this year as they are when the sun is at the peak of its activity, he says.

www.newscientist.com...

You can go to the AIM mission website to learn more about the research:

The Aeronomy of Ice in the Mesosphere (AIM) satellite mission is exploring Polar Mesospheric Clouds (PMCs), also called noctilucent clouds, to find out why they form and why they are changing.

The AIM mission has been extended by NASA through the end of FY12. During this time the instruments will monitor noctilucent clouds to better understand their variability and possible connection to climate change. Individual instrument data collection status, as well as spacecraft and instrument health, will be monitored throughout the life of the mission and reported periodically on this website.

aim.hamptonu.edu...

From NASA's AIM Mission website:
[atsimg]http://files.abovetopsecret.com/images/member/cc9e0e6dbbc9.jpg[/atsimg]

On June 11, 2007 the cameras on the AIM satellite returned some of the first data documenting noctilucent clouds over the Arctic regions of Europe and North America. This new data reveals the global extent and structure of these mysterious clouds, to a degree that was previously unattainable. White and light blue represent noctilucent cloud structures. Black indicates areas where no data is available. Credit: Cloud Imaging and Particle Size Experiment data processing team at the University of Colorado Laboratory for Atmospheric and Space Physics

www.nasa.gov...

Originally posted by Aggie Man
When I was a child my grandfather used to call those clouds "mares tales". in the winter time it was seen by my grandfather as a precursor for snow/ice storms.

Your grandfather was spot on, however there is a vast difference between cirrus clouds and noctilucent clouds.

Cirrus clouds are common and composed of ice crystals, existing between 20,000 and 45,000 feet (typically)

Noctilucent clouds are also composed of ice (and dust) and exist in the mesosphere rather than the troposphere. These clouds however only exist at higher latitudes, closwer to the arctic circle, while cirrus occurs everywhere.

Cirrus clouds are also one of the ten cloud types, in meteorological terms. Noctilucent are recognised, but not in these groups.

And ziggystar beat me to it with the reason why they (noctilucent clous) are thought to occur

As the solar minimum continues to deepen noctilucent clouds will appear in zones never thought possible. a 'typical' solar minimum generally lasts for 485 days. Current solar minimum 658 days.

thanks for the info shared here. i'll post some cloud pics i've taken recently.

[edit on 24-8-2009 by banned4life]

This August I was in Northern Italy by the Adriatic Sea (Lignano) and saw one of those clouds one night. It was really bright, as if it was lit by the moon, but it wasn't (and it was not smoke)... The cloud was rather small (smaller than the pics I could find) and dissolved in minutes, after I spotted it. Earlier today I was watching some youtube video, were they mentioned noctilucent clouds and I finally could identify what I saw...

Article in Wired