NASA takes AIM on noctilucent clouds

File:Iss017e011632.jpg

Noctilucent clouds photographed by the crew of the ISS. Date: 25 August 2008

From AIM. High up in the sky near the poles some 50 miles above the ground, silvery blue clouds sometimes appear, shining brightly in the night. First noticed in 1885, these clouds are known as noctilucent, or “night shining,” clouds. Their discovery spawned over a century of research into what conditions causes them to form and vary – questions that still tantalize scientists to this day. Since 2007, a NASA mission called Aeronomy of Ice in the Mesosphere (AIM) has shown that the cloud formation is changing year to year, a process they believe is intimately tied to the weather and climate of the whole globe.

“The formation of the clouds requires both water and incredibly low temperatures,” says Charles Jackman, an atmospheric scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., who is NASA’s project scientist for AIM. “The temperatures turn out to be one of the prime driving factors for when the clouds appear.”

So the appearance of the noctilucent clouds, also known as polar mesospheric clouds or PMCs since they occur in a layer of the atmosphere called the mesosphere, can provide information about the temperature and other characteristics of the atmosphere. This in turn, helps researchers understand more about Earth’s low altitude weather systems, and they’ve discovered that events in one hemisphere can have a sizable effect in another.

Since these mysterious clouds were first spotted, researchers have learned much about them. They light up because they’re so high that they reflect sunlight from over the horizon. They are formed of ice water crystals most likely created on meteoric dust. And they are exclusively a summertime phenomenon.

“The question people usually ask is why do clouds which require such cold temperatures form in the summer?” says James Russell, an atmospheric scientist at Hampton University in Hampton, Va., who is the Principal Investigator for AIM. “It’s because of the dynamics of the atmosphere. You actually get the coldest temperatures of the year near the poles in summer at that height in the mesosphere.”

As summer warmth heats up air near the ground, the air rises. As it rises, it also expands since atmospheric pressure decreases with height. Scientists have long known that such expansion cools things down – just think of how the spray out of an aerosol can feels cold – and this, coupled with dynamics in the atmosphere that drives the cold air even higher, brings temperatures in the mesosphere down past a freezing -210º F (-134 ºC).

Noctilucent clouds streaming across the sky in Utrecht, The Netherlands on June 16, 2009.

› Download video

Noctilucent clouds streaming across the sky in Utrecht, The Netherlands on June 16, 2009. Credit: Robert Wielinga

In the Northern hemisphere, the mesosphere reaches these temperatures consistently by the middle of May. Since AIM has been collecting data, the onset of the Northern season has never varied by more than a week or so. But the southern hemisphere turns out to be highly variable. Indeed, the 2010 season started nearly a month later than the 2009 season.

Atmospheric scientist Bodil Karlsson, a member of the AIM team, has been analyzing why the start of the southern noctilucent cloud season can vary so dramatically. Karlsson is a researcher at Stockholm University in Sweden, though until recently she worked as a post-doctoral researcher at the University of Colorado. A change in when some pretty clouds show up may not seem like much all by itself, but it’s a tool for mapping the goings-on in the atmosphere, says Karlsson.

“Since the clouds are so sensitive to the atmospheric temperatures,” says Karlsson. “They can act as a proxy for information about the wind circulation that causes these temperatures. They can tell us that the circulation exists first of all, and tell us something about the strength of the circulation.”

She says the onset of the clouds is timed to something called the southern stratospheric vortex – a winter wind pattern that circles above the pole. In 2010, that vortex lingered well into the southern summer season, keeping the lower air cold and interfering with cloud formation. This part of the equation is fairly straightforward and Karlsson has recently submitted a paper on the subject to the Journal of Geophysical Research. But this is not yet the complete answer to what drives the appearance of these brightly lit clouds.

AIM researchers also believe there is a connection between seemingly disparate atmospheric patterns in the north and south. The upwelling of polar air each summer that contributes to noctilucent cloud formation is part of a larger circulation loop that travels between the two poles. So wind activity some 13,000 miles (20,920 km) away in the northern hemisphere appears to be influencing the southern circulation.

The first hints that wind in the north and south poles were coupled came in 2002 and 2003 when researchers noticed that despite a very calm lower weather system near the southern poles in the summer, the higher altitudes showed variability. Something else must be driving that change.

Now, AIM’s detailed images of the clouds have enabled researchers to look at even day-to-day variability. They’ve spotted a 3 to10 day time lag between low-lying weather events in the north – an area that, since it is fairly mountainous, is prone to more complex wind patterns – and weather events in the mesosphere in the south. On the flip side, the lower atmosphere at the southern poles has little variability, and so the upper atmosphere where the clouds form at the northern poles stays fairly constant. Thus, there’s a consistent start to the cloud season each year.

“The real importance of all of that,” says Hampton’s Russell, “is not only that events down where we live can affect the clouds 50 miles (80 km) above, but that the total atmosphere from one pole to the next is rather tightly connected.”

Hammering out the exact mechanisms of that connection will, of course, take more analysis. The noctilucent cloud season will also surely be affected by the change in heat output from the sun during the upcoming solar maximum. Researchers hope to use the clouds to understand how the sun’s cycle affects the Earth’s atmosphere and the interaction between natural- and humankind-caused changes.

“These are the highest clouds in Earth’s atmosphere, formed in the coldest place in Earth’s atmosphere,” says Goddard’s Jackman. “Although the clouds occur only in the polar summer, they help us to understand more about the whole globe.”

AIM is a NASA-funded Small Explorers (SMEX) mission. NASA Goddard manages the program for the agency’s Science Mission Directorate at NASA headquarters in Washington. The mission is led by the Principal Investigator from the Center for Atmospheric Sciences at Hampton University in Virginia. The Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder, and the Space Dynamics Laboratory, Utah State University, built the instruments. LASP also manages the mission and controls the satellite.

Composite image of noctilucent cloud cover above the South Pole on December 31, 2009.

Looking down from above, AIM captured this composite image of the noctilucent cloud cover above the Southern Pole on December 31, 2009. The 2009 cloud season began a month earlier than the 2010 season did. Credit: NASA/HU/VT/CU LASP

› View larger

Advertisements

40 thoughts on “NASA takes AIM on noctilucent clouds

  1. The article said that Noctilucent clouds
    were “First noticed in 1885”. Have they only
    been forming since that time, or is it that it
    was not realized that they were that high until then?
    Just curious.

  2. Hey, Jimmy. Jim Hansen how can we spin this?? There has GOT to be a model somewhere we can “tinker” with.

  3. It seems each week that goes by there is a new discovery or explanation. Do we really know anything about the earths systems? And if we don’t why are we listening to a bunch of government employees with an agenda?

  4. @Wolf359.
    People have been observing the sky and documenting their findings for millennia. If it was first noticed in 1885, there is a real good chance it only just appeared in 1885. At least that was the first time in recorded history (going back maybe 5000 years).
    Think about it–sometimes there is a bright light in the sky after the sun sets. Wouldn’t some poet, religious theorist or speculator at least comment on that? Or maybe a scientist or mathematician positing that the earth is a sphere? The fact that it gets *no* mention prior to 1885 probably means it just wasn’t there until then. So there’s a good chance we are in some kind of unique condition that hasn’t been seen in 5000 years or more.
    That’s something to ponder, isn’t it?

  5. Massive Green Scandal exposed and Lawsuits pending.
    Green energy saving light bulbs “contain cancer causing chemicals”
    http://www.telegraph.co.uk/health/8462626/Energy-saving-light-bulbs-contain-cancer-causing-chemicals.html
    Their report advises that the bulbs should not be left on for extended periods, particularly near someone’s head, as they emit poisonous materials when switched on.
    Peter Braun, who carried out the tests at the Berlin’s Alab Laboratory, said: “For such carcinogenic substances it is important they are kept as far away as possible from the human environment.”
    The bulbs are already widely used in the UK following EU direction to phase out traditional incandescent lighting by the end of this year.
    But the German scientists claimed that several carcinogenic chemicals and toxins were released when the environmentally-friendly compact fluorescent lamps (CFLs) were switched on, including phenol, naphthalene and styrene.
    Andreas Kirchner, of the Federation of German Engineers, said: “Electrical smog develops around these lamps.
    “I, therefore, use them only very economically. They should not be used in unventilated areas and definitely not in the proximity of the head.”
    This Earth Hour remember switching off your low energy light bulb will not only save energy, it might also be saving your life.

  6. Fortunately, the intricate climate models have already allowed for the polar coupling and the seasonal regularity of these clouds otherwise they could not possibly have predicted the climate 100 years hence so accurately.
    Why is it, on such a regular basis, one reads about new discoveries of atmospheric effects or ocean currents or other factors that clearly impact climate which can not have been factored into the elaborate models, and yet the models are taken as gospel truth by the settled consensus?
    Just wondering?

  7. Interesting. Stephen Wilde, rbateman and I have been looking for a global balancing/interchange for a while, as metaphorically Earth’s poles are two sides of the same coin. Per my comment from last year:
    “Based on this chart by rbateman showing how well Antarctic and Arctic Sea Ice Anomalies match up;
    http://www.robertb.darkhorizons.org/seaice.anomaly.Ant_arctic.jpg”
    there certainly seems to be significant symmetry. Furthermore, in this animation of global pressure anomalies;
    http://www.cpc.noaa.gov/products/intraseasonal/z200anim.shtml
    note how the Arctic starts out as almost average pressure, and then as the pressure drops (becomes darker blue) over the Antarctic, the pressure increases (becomes dark red) over the Arctic. My potentially erroneous understanding of this effect, is that the Antarctic Vortex becomes very powerful (like a giant ice cold hurricane), creating very low pressure over Antarctica and increasing the pressure around the rest of the globe. If you watch the animation again, between June 10th and 20th it looks like a high pressure (dark red) pocket of more temperate air over the Atlantic gets pushed into Arctic. So when the Antarctic Vortex is strong/large, the pressure drops within it and increases around it (a positive Antarctic Oscillation) and the increased pressure forces warmer air towards the other pole.
    On a prior thread Stephen Wilde put forth the global sea ice balancing mechanism as this:
    “The Arctic is sea surrounded by land. The Antarctic is land surrounded by sea.
    When the mid latitude jets move poleward more solar shortwave energy gets into the oceans and in due course more energy from warming seas eventually penetrates into the Arctic ocean to reduce ice cover. That cannot happen in the Antarctic so the continental Antarctic just gets more isolated by the faster tighter run of jets around it and it cools whilst the Arctic warms.
    When the mid latitude jets move equatorward the seas receive less solar shortwave and so cool down and in due course the Arctic cools because it receives less energy from the waters entering the Arctic ocean. However the Antarctic warms because the slacker jets around the poles allow more north/south air flows and more warm air gets into the Antarctic continent.
    Thus the apparent short term stability of global ice cover. Arctic and Antarctic ice cover always moves in opposite directions but of course longer term variability does nevertheless affect global ice quantities for other reasons.”
    Can anyone else elaborate on the existence and function of Global Sea Ice balancing mechanisms that help to explain why the Global Sea Ice Area Anomaly;
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
    remains reasonably stable?”
    http://wattsupwiththat.com/2010/07/04/sea-ice-news-12/#comment-423147
    Also, Lief and I had an argument about a number of subjects including Polar Vortices a couple months ago, and this comment provides some good background on the subject:
    “I think that if and when the polar vortices coalesce into a single funnel during the Polar Winter and when in the Spring the coalesced funnel breaks up/down are key measures of the polar vortices. According to this paper on the Final Warming Date of the Antarctic Polar Vortex and Influences on its Interannual Variability;
    http://findarticles.com/p/articles/mi_7598/is_20091115/ai_n42654411/
    “several studies (including Waugh and Randel 1999; Waugh et al. 1999; Karpetchko et al. 2005; Black and McDaniel 2007) have indicated a trend over the 1980s and 1990s toward a later vortex breakdown.”
    This is a good paper exploring the Polar Vortices;
    http://www.columbia.edu/~lmp/paps/waugh+polvani-PlumbFestVolume-2010.pdf
    and the chart on page 10 shows the vortex break-up dates for the Northern Hemisphere since 1960 and Southern Hemisphere since 1979. Note that there appears to be a bit of disagreement in the literature as to whether the vortices break up or down, but either way, when it occurs, it seems to have a significant impact on Earth’s atmospheric circulation and oscillations. For example, this year the Arctic Polar Vortex does not appear to have coalesced yet;
    http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml
    and thus the multiple lobes of the uncoalesced Polar Vortex have reached down to lower latitudes this year, similar to what occurred in 1985:
    ” The January 1985 Arctic outbreak[1] was a meteorological event, the result of the shifting of the polar vortex further south than is normally seen.[1] Blocked from its normal movement, polar air from the north pushed into nearly every section of the eastern half of the United States, shattering record lows in a number of states.”
    http://en.wikipedia.org/wiki/January_1985_Arctic_outbreak
    This paper summarizes some of the differences between having a coalesced and uncoalesed polar vortex:
    http://www.ace.uwaterloo.ca/publications/Manney-ExtremeArcticWinters_ACP.pdf
    “The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was
    a record cold winter.”
    “Temperature and vortex evolution was very similar in the two years [2004 and 2006], with the vortex breaking down throughout the stratosphere, reforming quickly in the upper stratosphere, while remaining weak in the middle and (especially) lower stratosphere.”
    “2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March.”
    “Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.”
    This paper from Kniveton and Tinsley discusses the “Daily changes in global cloud cover and Earth transits of the heliospheric current sheet”:
    https://www.utdallas.edu/nsm/physics/pdf/tin_dcgcc.pdf
    E.M.Smith has had some interesting speculation in the area as well:
    http://chiefio.wordpress.com/2010/12/22/drakes-passage/
    This article states that polar vortices “are caused when an area of low pressure sits at the rotation pole of a planet. This causes air to spiral down from higher in the atmosphere, like water going down a drain.”
    http://www.universetoday.com/973/what-venus-and-saturn-have-in-common/I
    thus tonight I did a simple test in my kitchen sink. I filled it with water, pulled the plug, turned on the garbage disposal to add some vorticity and then right as the vortex was forming I hit the water to create a wave. The wave broke up the vortex. Rudimentary, but a basic proof of concept. My question is whether a CME, Solar Sector Boundary, a combination thereof, or other solar phenomenon, could sufficiently disturb and disrupt the magnetosphere as to precipitate the break up/down of a polar vortex.”
    http://wattsupwiththat.com/2011/02/16/watch-sunspot-group-1158-form-from-nothing/#comment-602054
    I think that Polar Vortices, and potentially Noctilucent Clouds, could represent one of the largest current gaps in our understanding of Earth’s climate system…

  8. Wow! No explicit caveat that it may be due to global warming! However, the pessimist in me says the wording, “First noticed in 1885” is their subtle offering to the gods of Catastrophic Anthropogenic CO2 Induced Global Warming.
    Those gods will read that this only started at the beginning of the Industrial revolution ramp-up. The peasant realists will read it that it was the 1st time that it was documented. And then there are the pessimists like me.

  9. -135 degrees … but affected by the temperature of the atmosphere ? that is a huge guess … they don’t know … they don’t even know if they are formed on space dust … they think they have an idea … i.e. a theory but they need real data …

  10. “Now, AIM’s detailed images of the clouds have enabled researchers to look at even day-to-day variability. They’ve spotted a 3 to10 day time lag between low-lying weather events in the north – an area that, since it is fairly mountainous, is prone to more complex wind patterns – and weather events in the mesosphere in the south. On the flip side, the lower atmosphere at the southern poles has little variability, and so the upper atmosphere where the clouds form at the northern poles stays fairly constant. Thus, there’s a consistent start to the cloud season each year.”
    Am I reading this right? Are they saying that the Northern clouds are controlled by conditions in the South Polar area and vice versa? The piece didn’t explain how; only a correlation which must mean causation.

  11. This earlier AIM article suggests that noctilucent clouds are on the increase and that Mars has them too..
    One other article I have seen suggests that the leftover debris of meteorites, in paricular Iron, that break apart in the upper atmosphere are responsible for noctilucent clouds.. Well.. we have seen an increase of these too.. as well..we have a season for all this..
    New satellites to solve mysteries of atmosphere
    NASA NEWS RELEASE
    Posted: May 7, 2004
    ..The Aeronomy of Ice in the Mesosphere (AIM) Small Explorer will determine the causes of Earth’s highest-altitude clouds, which occur on the very edge of space. These clouds form in the coldest part of the atmosphere, about 50 miles above the polar-regions, every summer. Recorded sightings of these silvery-blue, noctilucent or “night-shining” clouds began in the late 1800’s at high latitudes. They have been increasing in frequency and extending to lower latitudes over the past four decades.
    Scientists have hypothesized the more frequent occurrences may be an indicator of global warming, but until now they have not been able to test this idea. Since similar thin high altitude clouds have been observed at Mars, what AIM teaches us about Earth’s noctilucent clouds should help us understand the similarities and differences between the martian and terrestrial atmospheres. .
    http://www.spaceflightnow.com/news/n0405/07explorer/
    And another article for those who like data..
    Lidar observations of temperatures, waves, and noctilucent clouds at 69° N (Proceedings Paper)
    Author(s): Jens Fiedler; Gerd Baumgarten; Gotz von Cossart; Armin Schoch
    ..A subset of this data basis was used to determine the potential energy density to characterize the gravity wave activity above the station. Noctilucent clouds (NLC) are the highest clouds of the Earth’s atmosphere and a visible sign of extreme atmospheric conditions with temperatures far below radiative equilibrium. During the last 7 years a continuous data set with 1880 measurement hours was acquired during the summer seasons, of which 640 hours contain NLC signatures. This actually most extensive lidar acquired NLC archive was analyzed regarding brightness, altitude, vertical extent, as well as occurrence frequency of noctilucent clouds above ALOMAR..
    http://spie.org/x648.html?product_id=564772

  12. Wolf359, April 20, 2011 at 1:31 am:
    The article said that Noctilucent clouds
    were “First noticed in 1885″. Have they only
    been forming since that time, or is it that it
    was not realized that they were that high until then?
    Just curious.

    Not noticed by a degreed academician until then; nearly all ‘science’ works this way …
    Laymen are not allowed to pass on anything but “old wives’s tales” or ‘fishing stories’ amongst each other.
    /sarc (partially)

  13. Carla says:
    Your comment is awaiting moderation.
    April 20, 2011 at 5:58 am
    ~
    I am still wondering what role an increase of interstellar neon and argon would have on Earth’s elecrto atmospheric layers. Geesh with increased ionization coming from the additional GCR, add some neon and argon to your electo atmospheric layers.. or not..
    left field off now lol

  14. @Wolf359. Has anyone actually done adequate research of ancient texts to determine that this phenomenon was never mentioned before 1885?
    .1 seconds on Google produced a reference to Job 37:22, a verse which apparently shows an awareness of the aurora. What would 1000 seconds produce?
    Rogue waves didn’t exist until one scared the crap out of a “degreed academician”.

  15. “They’ve spotted a 3 to10 day time lag between low-lying weather events in the north – an area that, since it is fairly mountainous, is prone to more complex wind patterns – and weather events in the mesosphere in the south.”
    I think there must be something wrong with this sentence. Surely, it is the Arctic North that is flat and the South that is mountainous.
    Also, for one pole to react to events at the other in three days would seem to require that information about events at one pole travel to the other in (40000km /2) /72hours which Google tells me is 277kph. Maybe a bit less since the information wouldn’t have to travel quite half way around the world. But, none the less, really quickly. Is that credible? (I really have no idea).

  16. It is clear from Genesis 1 (5th Century BC?) that the sun was not responsible for daylight, else it would have been created before the first day. The Greeks seem to have been the first to notice a connection, apparently at about the time the heretical notion of a spherical earth came out. When the earth went from flat to round, the sun got blamed for lighting up the blue sky. In flat earth cosmologies the chief god was usually the sky god, progenitor of the sun and moon god.
    The reason nobody noticed the earth was round was because it wasn’t, of course. It changed shape 2500 years ago.

  17. First noticed in 1885 by European Man.
    1492 – America Discovered – Thanks European Man – Nothing to see here people already living in America
    1600’s – Sun became center of Solar System – Thanks European Man – Nothing to see here Mayan’s
    1885 – Noctilucent clouds 1st noticed – Thanks European Man – Nothing to see here Eskimo’s
    European Man knows all. If the Chinese disagree, well they are not European Man now are they.

  18. http://smallcomets.physics.uiowa.edu/www/faq.htmlx
    The link is to information about observations and research done in the 1980s by Louis Frank at the University of Iowa. In brief, Frank’s conclusions are the planets (at least earth) orbit the sun in a flux of small comets. They enter and are absorbed by earth’s atmosphere at a rate of several hundred per day. The comets are composed of mostly ice. They are the source of water fifty miles up – the precursor of noctilucent clouds. The small comet theory is wildly disruptive. It turns biology and geology upside down – sourcing all the water on earth in a three million year time-frame. But no one has refuted or disproved Frank’s observations. It is MOST interesting.

  19. This previous WUWT thread on noctilucent clouds is pertinent;
    http://wattsupwiththat.com/2010/06/04/noctilucent-clouds-may-be-more-visible-during-this-summer/
    particularly this quote from SpaceWeather.com:
    “There is a well-known correlation between noctilucent clouds and the solar cycle.
    NLC activity tends to peak during (and just after) years of solar minimum, possibly because low solar activity allows the upper atmosphere to cool, promoting the growth of ice crystals that make up the clouds. With the sun slowly emerging from a century-class minimum, the stage could be set for a good season of NLC watching.”
    and these charts:
    http://www.spaceweather.com/swpod2009/30may09/nlccorrelation.jpg?PHPSESSID=3fg2k6fp3b2gciomhaf9q86en5
    Also, this 2009 article from SpaceWeather.com;
    http://www.spaceweather.com/archive.php?view=1&day=14&month=07&year=2009
    states that:
    “2009 has been a good year for noctilucent clouds–and that’s no surprise. 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. Browse the gallery for observing tips and more snapshots from July 12th and 13th:”

  20. Why is it, that these “gee whizz” announcements NEVER answer the most elementary questions, that might come to mind about their “new” phenomenon.
    So these are “noctilucent” clouds meaning “night shining”.
    So if I get up at night, say midway, between sunset, and sunrise the next day; so that it truly is midnight, and the sun id around the other side of the earth, can I still see “noctilucent clouds” if there are any there of course.
    In other words; ARE THESE DARN THINGS SELF LUMINOUS ? ….. or are the just so gosh darn high, that evening sunlight still gets to them. The ONLY thing that has ever aroused my curiosity about noctilucent clouds, is do th4ey glow by themselves.
    Of course we know that they are a major cause of global warming, because high clouds warm the earth , and low clouds cool the earth, and the higher the clouds, the more they warm the earth; so Noctilucent clouds must really be cookers.
    Seems like I read about noctilucent clouds at least 50 years ago, in Popular Mechanics, so maybe these NASA chaps just aren’t old enough to know that they have been around a while.
    1885 was probably about the earliest that the chaps at the UEA CRU could catch a break from cooking the numbers on global anomalies, so that someone, finally said, let’s go see if we can find some noctilucent clouds.
    Sounds to me about like “ozone holes”; they don’t exist until somebody goes and looks for them.
    But bottom line, I AM in favor, of somebody trying to figure out what makes them tick. Something that is recognised as unusually weird, probably has some strange phenomena associated with it; and strange is always interesting to learn about.
    BUT WHY DO THEY LIGHT UP ??

  21. Temperature of -210º F (-134 ºC)
    Hmmm
    Above −78.51° C or −109.3° F, carbon dioxide changes directly from a solid phase to a gaseous phase through sublimation, or from gaseous to solid through deposition.
    Cold enough for CO2 to form CO2 ice crystals?
    Ozone? At –112 °C, it condenses.
    The occurance of NLC in NH is in sync with high ozone levels.

  22. Sorry, but if you need -134 oc for noctilucent clouds, then most of the clouds photographed over Utrecht in this posting are not noctilucent. Most of them are clearly contrails, with a possibility of a little noctilucent above them.
    .

  23. I was checking out some of the links left by some readers here. Btw thanks guys.
    Some historical notes on noctilucent clouds, along with possible resistive material and “electroluminescence”.. not a word I could have made up on my own thank you.. Some really farout, time period photos of noctilucent clouds in this doc..
    Otto Jesse and the Investigation of Noctilucent Clouds 115 Years Ago
    Wilfried Schröder
    Bremen-Roennebeck, Germany
    ABSTRACT
    Extracts from Otto Jesse’s papers relating to twilight studies, noctilucent clouds, and atmospheric movements are presented here to illustrate his contribution to the subject during the years 1884–1901. The most important result of his activity was the establishment of the Berlin Atmospheric Programme, which included regular monitoring of noctilucent clouds by visual and photographic means. Furthermore, Jesse studied problems of dynamic processes in noctilucent clouds and in the corresponding upper-atmospheric layers.
    3. Jesse’s results
    .. It was undoubtedly a pioneering achievement that Jesse succeeded in organizing the photographic monitoring of noctilucent clouds. From this he established the height of these clouds and found an average value of 82.08 km (Table 1), this value being confirmed by recent investigations (Bronšten and Grišin 1970). This was the first proof of the existence of cloudsat this height in the terrestrial atmosphere.
    .. Jesse could also demonstrate chaotic changes within single noctilucent clouds based on these photographs, which led to the conclusion that in this height range (80–85 km) wind fields have extremely rapid variations. Archenhold (1894) wrote on the observed changes in a noctilucent cloud: “The noctilucent cloud is, in its initial state, subject not only to very quick changes—new branches of the cloud
    .. Finally Jesse also established the annual changes of the frequency of occurrence of noctilucentclouds. Foerster remarked: “The clouds were observed in Berlin in the interval between the end of May and the end of July” (Foerster 1906, p. 53). As an early stage in his work, Jesse considered the origin of noctilucent clouds and their essential features (Jesse 1888). He discussed in this paper and in his study “Noctilucent clouds and their resistant material in general space” the connection between noctilucent clouds and the existence of a so-called resistant material.
    Archenhold (1928, p. 141) remarked about this hypothesis: “Jesse supposed that both seasonalchanges in the frequency of occurrence of noctilucent clouds and their movement could be easily explained if we suppose the existence of a resistant material in our solar system.” The notion of a resistant material is also discussed by Foerster (1906, 1911) in connection with noctilucent clouds. Some further consideration of the origin of noctilucent clouds was published by Archenhold (1894, p. 6): “In order to explain the sudden changes of the structures and visibility of noctilucentclouds, I propose that noctilucent clouds are due, not only to reflections of the Sun’s light, but toan optical phenomenon similar to that in vacuum tubes (Geisslerian tubes) due to electroluminescence”..
    http://journals.ametsoc.org/doi/pdf/10.1175/1520-0477%282001%29082%3C2457%3AOJATIO%3E2.3.CO%3B2

  24. Just The Facts says:
    April 20, 2011 at 9:52 am
    Funny how they were first noticed in 1885; 6 years after a solar minimum and 5 years before the next one; ie not far from solar maximum.

  25. Just The Facts says:
    April 20, 2011 at 4:33 am
    ..My question is whether a CME, Solar Sector Boundary, a combination thereof, or other solar phenomenon, could sufficiently disturb and disrupt the magnetosphere as to precipitate the break up/down of a polar vortex.”
    http://wattsupwiththat.com/2011/02/16/watch-sunspot-group-1158-form-from-nothing/#comment-602054
    I think that Polar Vortices, and potentially Noctilucent Clouds, could represent one of the largest current gaps in our understanding of Earth’s climate system…
    ~
    Great post JTF. And I love this little play on words here. .
    “I think that Polar Vortices, and potentially Noctilucent Clouds, could represent one of the largest current gaps in our understanding of Earth’s climate system…”
    “Current gaps” is like hitting the nail on the head. More like horizontal instead of vertical which is something that has been going around in my head.
    JTF.. it has already been suggested that solar impact on ionospheric winds may be ‘of’ the driving forces of polar vortex..
    I have to go back and read that post again..

  26. A G Foster says: April 20, 2011 at 7:53 am
    It is clear from Genesis 1 (5th Century BC?) that the sun was not responsible for daylight, else it would have been created before the first day.
    =====================
    5th Century BC for Genesis Authorship? You need to get caught up on your Archeology and Anthropology. It has been a long time since 1890 when that speculation was published. You are off by at least 800 years. I suggest you check out the Archaeological evidence cited in “Tyndale Bible Dictionary” by Walter A. Elwell and Philip Wesley Comfort (Google books). The best place to start is page 103-275.

  27. Just The Facts says:
    April 20, 2011 at 4:33 am
    =====================
    Thank you for your pin-point accuracy observations. Between you and Carla….I think we might be in the clear for at least the degradation of our own groupthink.
    Thank you ….seriously….thank you.
    Keep up the good work!
    Chris
    Norfolk, VA, USA

  28. @Wolf359
    There have been no mentioning of them before, which is very odd since they can be rather a spectacular view. Obviously this very strange appearance has been subject to all kinds of speculation, ranging from volcanic origins (Krakatao eruption was 2 years earlier) to, you might have guessed it, climate change. The latter is explainable by the theory mentioned in the article.

  29. Keith G wrote: “The fact that it gets *no* mention prior to 1885”
    You’ve been through every document and fireside myth since the dawn of mankind and *know* that noctilucent clouds have never been seen prior to 1885? You’ve vetted every fairytale and holy book for mentions of lights, spirits, gods, etc. in the sky that might possibly be references to this meteorological effect?
    As others have noted, this was probably the first time a scientist documented the effect without attributing it to gods and spirits.

  30. savethesharks says: April 20, 2011 at 10:05 pm
    Thank you for your pin-point accuracy observations. Between you and Carla….I think we might be in the clear for at least the degradation of our own groupthink.
    I am not sure I understand what you mean, can you elucidate? Are you still upset that I challenged Joe Bastardi to provide a robust accounting of his skill in long-range weather forecasting?

  31. So I see that “noctilucent” clouds, are NOT really “night shining” at all. They simply are high enough to still be in daylight. Whoopee !

  32. For Exif reading, you can use Photoshopped Image Killer. It reads software info and jpeg quantization tables from Exif. Specificially, it can tell you whether image has tags or quantization tables from Adobe Photoshop. The site is free.

Comments are closed.