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Noctilucent clouds


Marcel de Bont

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26 minutes ago, Marcel de Bont said:

While not strictly space weather related, a lot of people who chase aurora are also interested in noctilucent clouds and there seems to be an interest among the community to talk about it. This topic can be used to discuss this phenomenon.

Noctilucent-clouds-msu-6817.jpg

What an amazing photo!!!

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I have probably witnessed these many times.  I only remember them being at a comparatively high altitude, and typically only visible at dawn or sunset.  At those elevations I wouldn’t imagine anything but ice crystals. 

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3 minutes ago, hamateur 1953 said:

I have probably witnessed these many times.  I only remember them being at a comparatively high altitude, and typically only visible at dawn or sunset.  At those elevations I wouldn’t imagine anything but ice crystals. 

Apparently, rocket launches may affect the entry of water vapor into the mesosphere

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https://en.m.wikipedia.org/wiki/Noctilucent_cloud   Was just reading this fascinating subject matter in Wikipedia.  @KW2P and @Drax Spacex possibly also @WA1ZJL and @Glow Coat may be interested to learn that I read that they also exhibit high radar reflectivity from 50 mhz to 1.3 ghz!   Who knew??  Not me.  Haha. 

Edited by hamateur 1953
Added wiki link
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13 minutes ago, hamateur 1953 said:

that I read that they also exhibit high radar reflectivity from 50 mhz to 1.3 ghz

NLCs don't affect propagation directly, AFAIK. However, there recently was an interesting article in Dubus Magazin stating that mesospheric summer echoes (MSE) on VHF are much more likely when there are NCLs at night. MSE appear around summer solstice and around local noon. They are often confused with ionoscatter, however less ERP needed. Currently, propagation tests are being conducted in EU on 144 MHz for further explorations.

 

Ahoi

Pom

 

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Hmm. Well they just might.  Although personally I remain a bit puzzled over a substance ( iron) that is well known to us to be a very poor conductor of RF or anything for that matter, being the solitary source of E layer activity. Unless ionised of course.  Anyway  I wasn’t aware of any other tests regarding these.   Aircraft use 118-136mhz over here.  HF overseas  anyway you and @helios probably know more about those than me.  73 Mike 

51 minutes ago, Pom said:

NLCs don't affect propagation directly, AFAIK. However, there recently was an interesting article in Dubus Magazin stating that mesospheric summer echoes (MSE) on VHF are much more likely when there are NCLs at night. MSE appear around summer solstice and around local noon. They are often confused with ionoscatter, however less ERP needed. Currently, propagation tests are being conducted in EU on 144 MHz for further explorations.

 

Ahoi

Pom

 

There is an interesting situation in the states that occurs trans polar about this time of year on 50 mhz also.  Has been noted in QST over the last five years.  About a two week “ window” of opportunity.  

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59 minutes ago, Manuel said:

Do you guys know a way that might predict in advance when they'll be visible? Seems like they can be predictable just some hours before they occur.

You can use the OSWIN VHF Radar to check it, but as far as I know there is no chance to predict it like thunderstorms or rain. But I don't know it for sure. 

https://www.iap-kborn.de/en/research/department-radar-remote-sensing/current-radar-observations/oswin-mesosphere/

 

Clarification :

The link brings you to a now cast radar image of the mesosphere, if there are ice crystals you'll see it in the image. 

Edited by Ingolf
Clarification
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2 minutes ago, Manuel said:

Thanks mate! If there is "activity" and possibility of those clouds showing up i should see some like this. Right? 

Screenshot_20240626_175139.thumb.jpg.bc53248223f444f841fe417dde68131f.jpg

 

This is how it looks when a lot of ice is in the mesosphere. 

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There! Thanks, well, guess i'll have to check that radar, hoping for some clear nights even though being in Italy even if is north italy, i'll have less chances but never say never! 10th may is an example that uncommon things can happen 😁

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There are a lot of theories how the water comes into the mesosphere and show us NLC when the right angle to the sun is given. 

It is discussed that turbulences in the troposphere can induce water and there is the theory that maybe meteorites spread the water when it's iceshield is melting during atmosphere entry. 

This leads me to the "big bang" over the island of Elba that was confirmed by hundreds of witnesses. They don't know what it actually caused. Every evidence to investigate is gone. 

Maybe it was an ice meteorite that produced that big Shockwave and all the evidence is water in the mesosphere. 

The timing of that bang and the seen NLC after that bang would match. 

Clarification:

Meteorites don't bring pure water into the mesopause. They fall apart there and burn at maximum. This produce dust and particles. What happens to the particles is explained in a comment below. 

Edited by Ingolf
Typo / Clarification
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2 minutes ago, Ingolf said:

There are a lot of theories how the water comes into the mesosphere and show us NLC when the right angle to the sun is given. 

It is discussed that turbulences in the troposphere can induce water and there is the theory that maybe meteorites spread the water when it's iceshield is melting during atmosphere entry. 

This leads me to the "big bang" over the island of Elba that was confirmed by hundreds of witnesses. They don't know what is actually caused. Every evidence to investigate is gone. 

Maybe it was an ice meteorite that produced that big Shockwave and all the evidence is water in the mesosphere. 

The timing of that bang and the seen NLC after that bang would match. 

Pretty cool.  Hey @Ingolf  any idea what frequency those radars operate at?   Tnx. Mike 

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8 minutes ago, hamateur 1953 said:

Pretty cool.  Hey @Ingolf  any idea what frequency those radars operate at?   Tnx. Mike 

53.5 MHz 

I will add here some additional info's later if you want to. They use 144 Yagi Antennas with 4 elements each. Maximum power is 90Kw.

So it's not QRP 😂

 

Here is an English description of the radar system... 

 

https://www.iap-kborn.de/en/research/department-radar-remote-sensing/instruments/mst-radars/oswin-vhf-radar/

Edited by Ingolf
Typo
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Haha. Yes. Would need those HAARP amplifiers from University of Alaska!  And a Wurzburg Riese antenna array. Plus that is within our Six metre band over here.  Our FCC would take a dim view of my operating there!  73 Mike.   Very cool arrays @Ingolf  Radar technology is something I became interested in too especially when the evolution of Doppler made tracking natures vacuum cleaners in our midwest much simpler. It has saved a lot of lives.    

Edited by hamateur 1953
Acknowledging. Grammar typos
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20 hours ago, hamateur 1953 said:

I have probably witnessed these many times.  I only remember them being at a comparatively high altitude, and typically only visible at dawn or sunset.  At those elevations I wouldn’t imagine anything but ice crystals. 

The high altitude is given by the area where they occurring, it is just behind the mesosphere when water steam is transported into the extreme cold mesopause. Here is an convection with particles of dust and the water. The steam condensates at the particle. An ice crystal is born. 

Ice crystals can't shine by theirself logically, they only reflect the sunlight. 

That's why we mostly see NLC around the summer solstice and very late at sundown or very early at sunrise. The suns angle hast to be 6 to 16 degrees below the horizon to make the NLC visible for us. Means, the ice crystals are often there, we just don't see them caused by a wrong angle of the sunlight. 

Not very scientific written but as I am no scientist it's okay tho 🤷‍♂️☝️

1 hour ago, hamateur 1953 said:

Haha. Yes. Would need those HAARP amplifiers from University of Alaska!  And a Wurzburg Riese antenna array. Plus that is within our Six metre band over here.  Our FCC would take a dim view of my operating there!  73 Mike.   Very cool arrays @Ingolf  Radar technology is something I became interested in too especially when the evolution of Doppler made tracking natures vacuum cleaners in our midwest much simpler. It has saved a lot of lives.    

😂😂😂 You got me so hard. It took me all the time to realize the vacuum cleaners. I did not recognize the natural. I was wondering what kind of vacuum cleaner will give a radar signature and why the hell should someone want to know what room in the house is cleaned right now, observed by a doppler radar?! It's probably too hot today for brainwork and efficient reading 🔥😂

 

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Yes.   Nature’s vacuum cleaners are called Tornadoes over here.  They are unfortunately not always completely predictable in their paths etc.. And redistribution of things is particularly careless by and large.   🤣🤣

14 minutes ago, Ingolf said:

The high altitude is given by the area where they occurring, it is just behind the mesosphere when water steam is transported into the extreme cold mesopause. Here is an convection with particles of dust and the water. The steam condensates at the particle. An ice crystal is born. 

Ice crystals can't shine by theirself logically, they only reflect the sunlight. 

That's why we mostly see NLC around the summer solstice and very late at sundown or very early at sunrise. The suns angle hast to be 6 to 16 degrees below the horizon to make the NLC visible for us. Means, the ice crystals are often there, we just don't see them caused by a wrong angle of the sunlight. 

Not very scientific written but as I am no scientist it's okay tho 🤷‍♂️☝️

😂😂😂 You got me so hard. It took me all the time to realize the vacuum cleaners. I did not recognize the natural. I was wondering what kind of vacuum cleaner will give a radar signature and why the hell should someone want to know what room in the house is cleaned right now, observed by a doppler radar?! It's probably too hot today for brainwork and efficient reading 🔥😂

 

 

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I was thinking about temperature inversions and trapping of VHF transmissions also.  This used to be observed along our Southern coastline with regularity. Different from E layer activity whether auroral or incidentally from other activity. Fairly strong signals with less fading.   Always hard to be 100 percent sure of the way your signals get there as long as they do.  Haha.  

5 hours ago, UnderTheAnvil said:

NLCs are out in force tonight over Northern Europe!

Thanks to @Ingolf we can checkitout live now!  Cool. 

Edited by hamateur 1953
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"NLC is formed significantly higher than normal cloud cover, at a height of about 85 kilometers above the Earth, as a result of packing ice on particles, especially meteoric dust, high in the mesosphere. The phenomenon most often appears in the sky in the weeks around the summer solstice. Its visibility is significantly affected by high solar activity this year. The high regions of the Earth's atmosphere do not now have such stable conditions for the formation of NLCs as in previous years."
Source: Petr Horálek, astronomer

 

On June 20, 2017, my son was born in the early hours of the morning. At that time, it was possible to observe such a prominent NLC that it did not go below the horizon during the whole night. Between my wife's contractions, I occasionally looked out the window. It may not have been appropriate of me when my wife was in labor, but I couldn't help it.:rolleyes: I will always associate it with the birth of my son, one day I will tell him about it.
I have never seen such a clear NLC since.

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It’s really funny to me a former storm chaser that I missed the anvil topped tstorm reference by @UnderTheAnvil haha. I’m picturing a dude with his ears ringing figuring him to be a blacksmith!!! Hilarious @Ingolf should get a kick out of that after my silly “ Nature’s Vacuum Cleaners” reference! 🤣🤣🤣

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5 hours ago, hamateur 1953 said:

It’s really funny to me a former storm chaser that I missed the anvil topped tstorm reference by @UnderTheAnvil haha. I’m picturing a dude with his ears ringing figuring him to be a blacksmith!!! 

Haha no I'm no blacksmith! My ears do ring though. My name is a reference to the name I use on the netweather forums, but it's been a really poor year for thunderstorms in the UK, Europe has been hogging all the CAPE. Great year for atmospheric phenomena and that's why I decided to join up here!

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