# Talk:Noctilucent cloud

I added a link to a photograph of NLCs from Punta Arenas, maybe the only one image of a southern NLC taken from ground available on the net (also it's my first contribution to wikipedia :) -- nherm

Thanks, Nherm, and welcome to Wikipedia. You should think about creating a userpage for yourself. I hope to see more contributions! Denni☯ 02:53, 2005 August 10 (UTC)

It is mentioned in the main article that Manned Spaceflight is a contributing factor to the appearance of NLCs. Can someone please provide a reference for this conjecture? It is my understanding that at 82km altitude the intense UV-radiation from the sun dissociates water molecules very quickly. With half-life times of mere hours, its a little curious how these can be a contributing factor. Albester 18:14, 18 May 2006 (UTC)
Not sure how to indent a reply here (and the main article isn't editable by AC like me), but it looks like shuttle exhaust is more closely related to PMC/PMSE:
Stevens, M.H. et al., Antarctic mesospheric clouds formed from Space Shuttle exhaust, Geo. Res. Lett., 32, 2005.
Are you sure that the half-life is "mere hours" at the mesopause? The clouds are an almost permanent fixture in the polar summer, so I have a hard time believing that there's that much water being transported to that altitude. Also, here's a citation for the anthropogenic change "attribution needed":
Thomas, G., Are Noctilucent Clouds Harbingers of Global Change in the Middle Atmosphere?, Adv. Spc. Res., 32, 1737–1746, 2003.  —Preceding unsigned comment added by 69.91.134.125 (talk) 19:16, 8 November 2007 (UTC) 
Noctilucent Clouds in Popular Culture:
Also title of a song by Jim Cole and title of song by The Chromatics

This is pure nonsense but I believe that noctilucent clouds are physical manifestations of planetary wisdom (composed of frozen mist, illuminating the night, closest to empty space, poorly understood, and able to subsist at altitudes other clouds can't cut it at.  Keep up the good work brothers!
--68.56.0.116 (talk) 14:44, 11 December 2007 (UTC)

Does anybody know at which time of day, relative to sunset/sunrise, can noctilucent clouds be seen and on which latitudes? It would be nice to have graph displaying this in the article. --83.131.82.102 (talk) 11:38, 9 March 2008 (UTC)
I don't know if any of this might help http://www.netweather.tv/forum/index.php?showtopic=46972  —Preceding unsigned comment added by 92.21.136.202 (talk) 19:55, 18 June 2009 (UTC) 
also 
http://spaceweather.com/archive.php?view=1&day=18&month=06&year=2009

Convert templates for all units (mi to km, C to F)
Either the creation of new articles where there are red wikilinks, or their removal
Nbsps between numbers and their noun
That's the short list.  Thegreatdr (talk) 17:18, 7 October 2008 (UTC)

Wow, great job on the article, Reyk!  This one could be on the fast track to WP:FA!  One minor quibble with Thegreatdr, redlinks are a good thing, not a bad thing.  While it would be ideal for someone to make them into articles, they should not be removed if an article could be created in the future, they should be kept.  It is not a GA, or even an FA, disqualifier.
Thanks. I think the only red link remaining is the one for Otto Jesse; I'd start an article on him myslef beause he seems a notable person, but I can't find anything about him besides what's already in this atricle. Aside from that, all of Thegreatdr's suggestion have been taken care of, and I believe the good article criteria are met, so I'm off to nominate it now. I think it's still miles away from FA standard and probably not the kind of topic that becomes an FA anyway, but thanks for saying so. Thank you both for your help. Reyk YO! 01:23, 9 October 2008 (UTC)
See spoo (a former featured article).  NOTHING is too obscure for FA :) -RunningOnBrains 15:23, 9 October 2008 (UTC)
I have seen redlinks become a hindrance for FAC (see tropical cyclone).  In that article's case, it was because the red links for possible subarticles could have been (and were) used to help shorten the article, which was (and still is) large.  Thegreatdr (talk) 14:17, 8 April 2009 (UTC)

This review is transcluded from Talk:Noctilucent cloud/GA1. The edit link for this section can be used to add comments to the review.
Hi, I'll be reviewing the article. All I know about noctilucent clouds I learned on Slashdot. The review should be posted within a couple of days. Wronkiew (talk) 16:21, 16 October 2008 (UTC)


### Overview
GA review (see here for criteria)
It is reasonably well written.
a (prose):  b (MoS): 

It is factually accurate and verifiable.
a (references):  b (citations to reliable sources):  c (OR): 

It is broad in its coverage.
a (major aspects):  b (focused): 

It follows the neutral point of view policy.
Fair representation without bias: 

It is stable.
No edit wars etc.: 

It is illustrated by images, where possible and appropriate.
a (images are tagged and non-free images have fair use rationales):  b (appropriate use with suitable captions): 

Overall:
Pass/Fail: 


### Prose
"Noctilucent clouds, also known as polar mesospheric clouds, are bright cloudlike phenomena in the upper atmosphere, visible in a deep twilight." Should be "cloud-like".
Done.
"The exhaust from space shuttles, which is almost entirely water vapour, has been found to generate individual clouds." This should be capitalized.
Done.
"Noctilucent clouds are composed of tiny crystals of water ice 40 to 100 nanometers in diameter and exist at a height of approximately 85 kilometres (53 mi),higher than any other clouds in Earth's atmosphere." Replace "approxmimately" with "about". Also, this is missing a space after "(53 mi),".
Done
"As the mesosphere contains very little moisture, approximately one hundred millionth that of air from the Sahara desert, and is extremely thin, the ice crystals can only form at temperatures below about −120 °C (−184.0 °F)." Replace "approximately" with "about". Numbers above 10 should be written with numerals, but I'm not sure how to fix this case.
I've left this as it is for now. I'm not sure what to do about it either.
"These showed for the first time that the occurence of the clouds coincided with very low temperatures in the mesosphere." Fix spelling.
Done.
"Wegener correctly conjectured that they were composed of water ice." If "conjectured" is really a word, it's an uncommon one. Maybe replace with "Wegener's conjecture that...was later proven to be correct".
Conjectured is a word but I've changed it anyway because I think your version reads better.
"On August 28, 2006, scientists with the Mars Express mission announced that they found clouds of carbon dioxide similar to noctilucent clouds over Mars that extended up to 100 km above the surface of the planet." This paragraph is too short. Either develop it further or combine it with another one. Also, the relationship between CO2 clouds on Mars and noctilucent clouds on Earth could use more explaining.
Done.
"A classification scheme was developed by Fogle in 1970 that distinguished between five different forms." Generally, "between" distinguishes two different forms. Maybe replace with "differentiated five forms".
I've changed this to An identification scheme was developed by Fogle in 1970 that classified five different forms.
"Climate models predict that increased greenhouse gas emissions cause a cooling of the mesosphere, which would lead to more frequent and widespread occurences of noctilucent clouds." Fix spelling.
Done.
"There are also noctilucent clouds made of smaller crystals, 30nm or less, which are invisible to observers on the ground because they do not scatter enough light." In general, avoid the using "there" as a placeholder for a missing subject in a sentence. Start this one with "Also, some noctilucent clouds are".
Done
Combine the last two paragraphs in the "Formation" section about sodium deposition and radar reflectivity.
Done.
"His notes provide evidence that noctilucent clouds first appeared in 1885; he had been doing detailed observations of the unusual sunsets caused by the Krakatoa eruption the previous year and firmly believed that, if the clouds had been visible then, he would undoubtedly have noticed them." Break up this long sentence.
Changed the semicolon into a full stop.


### MoS
Lead section
Latin translation is explained in the lead but not later in the article
Altitude is given in the lead but not in a later section
Layout
Some entries in the external links section need better descriptions, like "More pictures", and "BBC News Article on satellite mission".
Words to avoid
"They are frequently regarded as being quite beautiful." Maybe a quote would work better here.
"It has been pointed out that the first sightings coincide with the Industrial Revolution and they have become more widespread and frequent throughout the 20th century." Even with the citation, this is not specific enough considering how controversial it is. Name the pointer.
"It has been suggested that a transition to a hydrogen economy could increase the number of noctilucent clouds through increased emissions of free hydrogen." Again, name the suggester.
These are all done. Reyk YO! 03:06, 19 October 2008 (UTC)


### References
Usage of "Notes" and "References" sections should be consistent, or at least logical. Why are some references listed in the notes section?
Most of the references are single-page websites which can be directly referenced within the in-line citation, and I can quite easily cite them several times if I have to (such as the first Phillips reference). But there are a few instances where I've cited specific pages of a longer document (Gadsden & Parviainen, and Schroeder). There it would be cumbersome and untidy to constantly have to include the full information of the document for each inline citation so I've abbreviated it to, say, "Gadsden & Parviainen (2006), p. 13" and stated the full document information just once, in the References section. This is how other good articles, such as The Hobbit, organize things.
Web site citations should have either authors or publishers named. For example, http://www.albany.edu/faculty/rgk/atm101/nlc.htm was written by Robert G. Keesee and was published by University at Albany.
Some of the journal abstracts and books need much better citations so interested readers can easily find them. Examples:
Karlsson, B.; Gumbel, J.; Stegman, J.; Lautier, N.; Murtagh, D. P.; The Odin Team (2004). "Studies of Noctilucent Clouds by the Odin Satellite" (PDF). 35th COSPAR Scientific Assembly: 1921. Bibcode:2004cosp...35.1921K. Retrieved 2008-10-16.{{cite journal}}:  CS1 maint: multiple names: authors list (link)
Hervig, Mark; Thompson, Robert E.; McHugh, Martin; Gordley, Larry L.; Russel, James M.; Summers, Michael E. (2001). "First Confirmation that Water Ice is the Primary Component of Polar Mesospheric Clouds". Geophysical Research Letters. 28 (6): 971–974. Bibcode:2001GeoRL..28..971H. doi:10.1029/2000GL012104. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
Gadsen, M. (1975). "Observations of the colour and polarization of noctilucent clouds". Annales de Geophysique. 31: 507–516. Bibcode:1975AnG....31..507G. {{cite journal}}: Unknown parameter |month= ignored (help)
Gadsden, M. (1995). Observing Noctilucent Clouds (PDF). International Association of Geomagnetism & Aeronomy. ISBN 0965068609. Retrieved 2008-10-16. {{cite book}}: Unknown parameter |coauthor= ignored (|author= suggested) (help)


### Attribution
Apparent contradiction: "are bright cloudlike phenomena" vs. "normally too faint to be seen".
Removed the word "bright". I guess the clouds are bright compared to the night sky but faint compared to a daylight sky, but anyway...
"they are too high to be reached by weather balloons" Needs a reference.
Removed that bit.
"located in the mesosphere at altitudes of around 75 to 85 kilometers (47 to 53 mi)" Needs a reference.
Found one. :)
"The dust is believed to come from micrometeors although volcanoes and dust lifted upwards from the troposphere are also possibilities." Needs references and a comma.
Added the comma. The sentence is supported by reference #5.
"About half of the vapor is injected in the thermosphere, typically at altitudes of 103 to 114 kilometers (64 to 71 mi)." Needs a reference. You'll find it in the US Navy press release in the external links section. Also, this sentence is lifted directly from the press release.
Done. That sentence was one of the few bits left over from how the article was before I stared on it.
"Studies have shown that this exhaust can be transported to the Arctic region in little over a day, although the exact mechanism of this very high-speed transport is unknown." Best to just name one study and then cite it. This article has a noticeably high number of ambiguous references to studies, measurements, and experiments. Also, in uncontroversial cases you can delete the "studies have shown" phrase and just state the results, as long as you have appropriate citations.
Done.
A duplicate citation closer to Bellan's name would be nice.
Done.
"Study was limited to ground-based observations and scientists had very little knowledge of the mesosphere until the 1960s, when direct rocket measurements began." Needs a reference for the lack of knowledge and a comma somewhere.
Done.
"Noctilucent clouds were first detected from space by an instrument on the OGO-6 satellite in 1972." This definitely needs a reference.
Done.


### Images
Image:Northpoleclouds AIMData c.jpg may not be a NASA image, and therefore would not be PD. I sent an email to the University of Colorado asking for clarification.
I've taken the image out for the time being. Reyk YO! 04:05, 19 October 2008 (UTC)


### Comments
Nice work, I'm sure you'll have this fixed up in no time. I tried to be specific, but if you have any questions, just let me know. Wronkiew (talk) 03:43, 18 October 2008 (UTC)
Article is GA quality. Nice work. Wronkiew (talk) 04:49, 19 October 2008 (UTC)

Thanks. That was some really thorough auditing you did, very much appreciated. Reyk YO! 05:00, 19 October 2008 (UTC)

I'd like to suggest that the search for polar mesospheric clouds not be automatically redirected to noctilucent clouds. Though the same tenuous ice crystal layer in the mesophere produces both physical phenomena, noctilucent clouds are the phenomena observed from the ground and polar mesospheric clouds are the scattering layer observed by satellite and LIDAR instrumentation. It is a subtle, but important distinction. I created a new article called Polar Mesospheric Clouds last night and would appreciate help writing and editing it.—Preceding unsigned comment added by Rss100001 (talk • contribs) 

I agree with the new redirects. Good job on the new article, although it needs some reliable sources. -RunningOnBrains(talk page) 19:59, 10 June 2009 (UTC)
On second thought, as it seems the consensus is that these are the same phenomenon, why should it not all appear in the same article? -RunningOnBrains(talk page) 20:07, 10 June 2009 (UTC)

http://spaceweather.com/archive.php?view=1&day=18&month=06&year=2009
http://www.newscientist.com/article/dn17234-mysterious-nightshining-clouds-may-peak-this-year.html  —Preceding unsigned comment added by 81.132.14.185 (talk) 07:44, 19 June 2009 (UTC) 
I suggest including a reference to increased prevalence of noctilucent clouds during solar minima in the article, since there is considerably more evidence for this than for increased prevalence due to climate change.  Not to discount that possibility as well, of course, but having every imaginable kind of aberration that occurs being attributed to climate change is getting a little tedious and is damaging the credibility of climatology.   
TwoGunChuck (talk) 18:09, 12 August 2009 (UTC)

Two photos in different sections are near-duplicates. Remove one?
Cognita (talk) 05:54, 30 June 2009 (UTC)

The first observation statement (first in section Discovery and investigation):

Noctilucent clouds were first observed in 1885, two years after the 1883 eruption of Krakatoa.[4]
is extremely unlikely! The source says:

A British sky watcher named Thomas William Backhouse was perhaps the first to notice the odd blue wisps in 1885, and many scientists thought that the phenomenon was an atmospheric effect caused by ash thrown up by the gigantic volcanic eruption of Krakatoa in Indonesia two years earlier.
(my underlinings indicating the invalid citation usage) but living in Sweden and accidentally observing them every other summer, I think we should disregard that statement as speculative nonsense. It's infinitely more likely some Scandinavian, some Russian or Canadian scientist noted them much earlier. ... said: Rursus (bork²) 13:30, 14 July 2009 (UTC)

What is the basis for claiming that these clouds weren't observed before 1885??? To the ordinary observer, they appear as normal clouds, albiet faint and silvery in the late evening and early morning. We only regard them as unusual today because we have instruments to measure their extreme height. So prior to the late 19th century, most scientific observers would have found them indistinguishable from late night cirrus clouds. This section of the article seems like the laziest kind of conjecture...
Do you mean, "Why does that article claim they were only discovered in 1885"? That's easy: it's because that is what all the sources say. I have been scrupulous in recording only what can be attributed to reliable secondary sources, and no more- and that claim is attributed to two separate sources. Reyk YO! 02:44, 20 July 2010 (UTC)

Hello! This is a note to let the editors of this article know that File:Helkivad ööpilved Kuresoo kohal.jpg  will be appearing as picture of the day on March 22, 2012. You can view and edit the POTD blurb at Template:POTD/2012-03-22. If this article needs any attention or maintenance, it would be preferable if that could be done before its appearance on the Main Page so Wikipedia doesn't look bad. :) Thanks! ~AH1 (discuss!) 01:48, 22 March 2012 (UTC) 

Nice! Thanks for the heads up. Reyk YO! 04:15, 22 March 2012 (UTC)

A recent article I found on science daily, referencing a NASA report where the investigators/authors believe that 3 things are needed to form NLCs are cold temps, water vapor and space dust. Here is the citation info copied from the sciencedaily page:
NASA/Goddard Space Flight Center. "Appearance of night-shining clouds has increased." ScienceDaily. ScienceDaily, 11 April 2014. <www.sciencedaily.com/releases/2014/04/140411091939.htm>.  Just passing this along. Accidental contributor (talk) 06:10, 7 May 2014 (UTC)

Thanks, nice find! Reyk YO! 06:14, 7 May 2014 (UTC)

A Wikipedia editor had provided a link to a site by the Australian Government Antarctic Division (http://www.antarctica.gov.au/about-antarctica/environment/atmosphere/noctilucent-clouds).  I removed the link because within the story itself the same comment was only provided as conjecture with no source data to back it up.  To whit, the article stated "It has been alternatively claimed that the appearance of noctilucent clouds is the earliest evidence of anthropogenic climate change." This was the identical text within the Wikipedia entry and with no source links or evidence to back up the claim.  These clouds have been observed since the 19th century, before the time that industrialization could have been claimed to cause anthropogenic global warming.  As was stated above in the talk section, they were not recorded before because up until that time there was no reason to suspect these clouds were different than normal cirrus clouds other than in luminosity.  This does not mean they did not exist prior to 1885, just as we cannot say atoms did not exist prior to the 19th century just because we did not have the means or science to measure or even theorize them.  — Preceding unsigned comment added by Herefordnuthouse (talk • contribs) 15:03, 31 May 2014 (UTC)

I provided more substantial citations.--Smkolins (talk) 17:17, 31 May 2014 (UTC)

Basically the same subject. Pierre cb (talk) 13:36, 1 August 2021 (UTC)

i agree , and i found it odd that both wiki and cloudatlas list 3 genus of clouds that exist above Tropospheric level , but wiki for some reason splits noctilucent clouds as 2 and merge the 2 Stratospheric clouds into one
wiki: 1 stratospheric cloud | 2 mesospheric clouds
cloudatlas:2 stratospheric clouds | 1 mesospheric cloud
however the noctilucent clouds have 5 different (species,types,viarients?) it seems Joshoctober16 (talk) 02:50, 4 August 2021 (UTC)
I agree. A merge sounds like a good idea. Reyk YO! 09:22, 4 August 2021 (UTC)
  Y Merge completed Klbrain (talk) 22:03, 19 December 2021 (UTC)

I am concerned that this article no longer meets the good article criteria due to uncited text, particularily in the "Description from satellites" section. Is anyone willing to address this concern, or should this go to WP:GAR? Z1720 (talk) 02:47, 27 October 2024 (UTC)


### Noctilucent cloud