392:. It remains unclear whether their appearance had anything to do with the volcanic eruption or whether their discovery was due to more people observing the spectacular sunsets caused by the volcanic debris in the atmosphere. Studies have shown that noctilucent clouds are not caused solely by volcanic activity, although dust and water vapour could be injected into the upper atmosphere by eruptions and contribute to their formation. Scientists at the time assumed the clouds were another manifestation of volcanic ash, but after the ash had settled out of the atmosphere, the noctilucent clouds persisted. Finally, the theory that the clouds were composed of volcanic dust was disproved by Malzev in 1926. In the years following their discovery, the clouds were studied extensively by Otto Jesse of
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This indicates that control of polar mesospheric clouds is determined by geographical rather than geomagnetic factors. The brightness of polar mesospheric clouds and noctilucent clouds appears to be consistent at the latitudes where both are observed, but polar mesospheric clouds near the pole are much brighter than noctilucent clouds, even taking into account the lower sky background seen from space. Polar mesospheric cloud observations have revealed that the well-known phenomenon of the northward shifting with latitude of date of peak noctilucent cloud occurrence is partly due to the increased number of hours of noctilucent cloud visibility with latitude and partly due to an actual northward retreat of the boundary towards the end of the season.
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satellite, was the first to trace noctilucent-like cloud layers across the polar cap. The very bright scattering layer was seen in full daylight conditions, and was identified as the poleward extension of noctilucent clouds. In the early 1980s, the layer was observed again from a satellite, the Solar
Mesospheric Explorer (SME). On board this satellite was an ultraviolet spectrometer, which mapped the distributions of clouds over the time period 1981 to 1986. The experiment measured the altitude profile of scattering from clouds at two spectral channels (primarily) 265 nm and 296 nm. This phenomenon is now known as Polar Mesospheric Clouds.
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summer solstice and ends about two months afterwards. Since there are no biases due to such factors as changing number of hours of visibility, weather conditions, etc. this is a âtrueâ behaviour. It is believed to be a result of the fact that summertime mesopause region becomes coldest during this period causing water-ice to form, in contrast to most other regions of the atmosphere which are warmest in summer. Temperatures at latitudes equatorward of the boundary of detection never get low enough for water-ice to form.
396:, who was the first to photograph them, in 1887, and seems to have been the one to coin the term "noctilucent cloud". 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. Systematic photographic observations of the clouds were organized in 1887 by Jesse,
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706:. They are best seen when the Sun is between 6° and 16° below the horizon. Although noctilucent clouds occur in both hemispheres, they have been observed thousands of times in the northern hemisphere, but fewer than 100 times in the southern. Southern hemisphere noctilucent clouds are fainter and occur less frequently; additionally the southern hemisphere has a lower population and less land area from which to make observations.
236:
415:'s conjecture, that they were composed of water ice, was later shown to be correct. Study was limited to ground-based observations and scientists had very little knowledge of the mesosphere until the 1960s, when direct rocket measurements began. These showed for the first time that the clouds' occurrence coincided with very low temperatures in the mesosphere.
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interference from the very bright Earth about a degree beneath the cloud layer. It is a much more difficult task to observe the clouds against the bright background of the illuminated Earth, although this has been achieved in the ultraviolet in the 200 to 300 nm spectral region, because of the very small albedo of the earth in this part of spectrum.
324:, and is extremely thin, the ice crystals can form only at temperatures below about â120 °C (â184 °F). This means that noctilucent clouds form predominantly during summer when, counterintuitively, the mesosphere is coldest as a result of seasonally varying vertical winds, leading to cold summertime conditions in the upper mesosphere (
560:. This holds true for both hemispheres. Great variability in scattering is observed from day-to-day and year-to- year, but averaging over large time and space scales reveals a basic underlying symmetry and pattern. The long- term behaviour of polar mesospheric cloud frequency has been found to vary inversely with solar activity.
455:) satellite was launched on 25 April 2007. It was the first satellite dedicated to studying noctilucent clouds, and made its first observations a month later (25 May). Images taken by the satellite show shapes in the clouds that are similar to shapes in tropospheric clouds, hinting at similarities in their dynamics.
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Polar mesospheric clouds generally increase in brightness and occurrence frequency with increasing latitude, from about 60 degrees to the highest latitudes observed (85 degrees). So far, no apparent dependence on longitude has been found, nor is there any evidence of a dependence on auroral activity.
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Satellite observations allow the very coldest parts of the polar mesosphere to be observed, all the way to the geographic pole. In the early 1970s, visible airglow photometers first scanned the atmospheric horizon throughout the summer polar mesospause region. This experiment, which flew on the OGO-6
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region in little over a day, although the exact mechanism of this very high-speed transfer is unknown. As the water migrates northward, it falls from the thermosphere into the colder mesosphere, which occupies the region of the atmosphere just below. Although this mechanism is the cause of individual
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The general seasonal characteristics of polar mesospheric clouds are well established from the five years of continuous SME data. Over that period, data for four cloud âseasonsâ in the north, and five âseasonsâ in the south were recorded. In both hemispheres, the season begins about one month before
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When mesospheric clouds are viewed above the atmosphere, the geometrical limitations of observing from the ground are significantly reduced. They may be observed âedge-onâ against the comparatively dark sky background, even in full daylight. The photometer field of view must be well baffled to avoid
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because the Sun is never low enough under the horizon at this season at these latitudes. Noctilucent clouds form mostly near the polar regions, because the mesosphere is coldest there. Clouds in the southern hemisphere are about 1 km (3,300 ft) higher than those in the northern hemisphere.
698:), and closer to the poles it does not get dark enough for the clouds to become visible. They occur during summer, from mid-May to mid-August in the northern hemisphere and between mid-November and mid-February in the southern hemisphere. They are very faint and tenuous, and may be observed only in
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American and Soviet astronauts observed the phenomenon from space as early as 1970. Most observations are reported from the night side of the orbit and the observer is looking towards the twilight sector. At this time the observer's eye is dark-adapted and polar mesospheric clouds would appear with
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and settle into a layer just above the altitude of noctilucent clouds, and measurements have shown that these elements are severely depleted when the clouds are present. Other experiments have demonstrated that, at the extremely cold temperatures of a noctilucent cloud, sodium vapour can rapidly be
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to create an artificial noctilucent cloud. The cloud was to be observed over a period of weeks or months by ground instruments and the
Spatial Heterodyne IMager for MEsospheric Radicals (SHIMMER) instrument on the NRL/STP STPSat-1 spacecraft. The rocket's exhaust plume was observed and reported to
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and satellites have been tracking the decrease in brightness of the clouds with the increase of ultraviolet radiation for the last two solar cycles. It has been found that changes in the clouds follow changes in the intensity of ultraviolet rays by about a year, but the reason for this long lag is
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Robinson made a series of interesting observations between 1849 and 1852, and two of his entries in May 1850 may describe noctilucent clouds. On 1 May 1850, he notes âstrange luminous clouds in NW, not auroral'. This does seem like NLCs even though early May is outside the typical NLC 'window';
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PMC's have four major types based on physical structure and appearance. Type I veils are very tenuous and lack well-defined structure, somewhat like cirrostratus or poorly defined cirrus. Type II bands are long streaks that often occur in groups arranged roughly parallel to each other. They are
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A 2018 experiment briefly created noctilucent clouds over Alaska, allowing ground-based measurements and experiments aimed at verifying computer simulations of the phenomenon. A suborbital NASA rocket was launched on 26 January 2018 by
University of Alaska professor Richard Collins. It carried
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in the path of the sunlight illuminating the noctilucent cloud. They can appear as featureless bands, but frequently show distinctive patterns such as streaks, wave-like undulations, and whirls. They are considered a "beautiful natural phenomenon". Noctilucent clouds may be confused with
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usually more widely spaced than the bands or elements seen with cirrocumulus clouds. Type III billows are arrangements of closely spaced, roughly parallel short streaks that mostly resemble cirrus. Type IV whirls are partial or, more rarely, complete rings of cloud with dark centres.
466:âcrystal clouds on Mars that extended to 100 km (330,000 ft) above the planet's surface. These are the highest clouds discovered over the surface of a rocky planet. Like noctilucent clouds on Earth, they can be observed only when the Sun is below the horizon.
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water-filled canisters, which were released at about 53 mi (85 km) above the Earth. Since the naturally-occurring clouds only appear in summer, this experiment was conducted in mid-winter to assure that its results would not be mixed with a natural event.
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The clouds may show a large variety of different patterns and forms. An identification scheme was developed by Fogle in 1970 that classified five different forms. These classifications have since been modified and subdivided. As a result of recent research, the
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Observed from the ground, this phenomenon is known as noctilucent clouds. From satellites, PMCs are most frequently observed above 70â75° in latitude and have a season of 60 to 80 days duration centered about a peak which occurs about 20 days after the
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in diameter and exist at a height of about 76 to 85 km (249,000 to 279,000 ft), higher than any other clouds in Earth's atmosphere. Clouds in the Earth's lower atmosphere form when water collects on particles, but
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Hervig, Mark; Thompson, Robert E.; McHugh, Martin; Gordley, Larry L.; Russel, James M.; Summers, Michael E. (March 2001). "First
Confirmation that Water Ice is the Primary Component of Polar Mesospheric Clouds".
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in five days. The giant balloon was loaded with cameras, which captured six million high-resolution images filling up 120 terabytes of data storage, aiming to study the PMCs which are affected by the atmospheric
671:, but appear sharper under magnification. Those caused by rocket exhausts tend to show colours other than silver or blue, because of iridescence caused by the uniform size of the water droplets produced.
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Noctilucent clouds are generally colourless or pale blue, although occasionally other colours including red and green have been observed. The characteristic blue colour comes from absorption by
434:, even when they were not visible to the naked eye. The first physical confirmation that water ice is indeed the primary component of noctilucent clouds came from the HALOE instrument on the
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203:. There are now doubts concerning Robinson's out-of-season records, partly as a result of observations, from several points around high northern latitudes, of NLC-like phenomena after the
620:, resulted from air being pushed up by mountain ranges all the way up to the mesosphere. These images would aid in studying turbulence in the atmosphere, and consequently better
925:
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Murray, B.J.; Plane, J.M.C. (2005). "Uptake of Fe, Na and K atoms on low-temperature ice: implications for metal atom scavenging in the vicinity of polar mesospheric clouds".
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422:-6 satellite in 1972. The OGO-6 observations of a bright scattering layer over the polar caps were identified as poleward extensions of these clouds. A later satellite, the
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emissions produce additional water vapor through chemical reactions once the methane molecules reach the mesosphere â creating, or reinforcing existing, noctilucent clouds.
713:. Also, some noctilucent clouds are made of smaller crystals, 30 nm or less, which are invisible to observers on the ground because they do not scatter enough light.
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satellite suggests that noctilucent clouds require water vapour, dust, and very cold temperatures to form. The sources of both the dust and the water vapour in the
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maximum contrast against a comparatively dark background. Soviet astronauts have reported sightings of mesospheric clouds even when the Sun is above the horizon.
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from the Sun breaks water molecules apart, reducing the amount of water available to form noctilucent clouds. The radiation is known to vary cyclically with the
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Type II bands are long streaks that often occur in roughly parallel groups, usually more widely spaced than the bands or elements seen with cirrocumulus clouds.
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to 1.3 GHz. This behaviour is not well understood but a possible explanation is that the ice grains become coated with a thin metal film composed of
375:, which makes the cloud far more reflective to radar, although this explanation remains controversial. Sodium and iron atoms are stripped from incoming
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at a height of about 46 km (151,000 ft), was found to generate minuscule individual clouds. About half of the vapour was released into the
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Thomas, G. E.; Olivero, J. J. (20 October 1989). "Climatology of polar mesospheric clouds: 2. Further analysis of solar mesosphere explorer data".
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1672:"Two-dimensional turbulence, space shuttle plume transport in the thermosphere, and a possible relation to the Great Siberian Impact Event"
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Hart, V. P.; Taylor, M. J.; Doyle, T. E.; Zhao, Y.; Pautet, P.-D.; Carruth, B. L.; Rusch, D. W.; Russell III, J. M. (11 January 2018).
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around sunrise and sunset when the clouds of the lower atmosphere are in shadow, but the noctilucent cloud is illuminated by the
426:, mapped the distribution of the clouds between 1981 and 1986 with its ultraviolet spectrometer. The clouds were detected with a
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2007:
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performed spectral analyses on the clouds, and produced daily global maps that revealed large patterns in their distribution.
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Thomas, Gary E (September 1984). "Solar
Mesosphere Explorer measurements of polar mesospheric clouds (noctilucent clouds)".
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No confirmed record of their observation exists before 1885, although they may have been observed a few decades earlier by
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Murray, B.J.; Jensen, E.J. (2000). "Homogeneous nucleation of amorphous solid water particles in the upper mesosphere".
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entry of
February 2013 (outside the NLC season) that were actually stratospheric dust reflections visible after sunset.
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Hultgren, K.; et al. (2011). "What caused the exceptional mid-latitudinal
Noctilucent Cloud event in July 2009?".
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3525:
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2045:"Investigating Gravity Waves in Polar Mesospheric Clouds Using Tomographic Reconstructions of AIM Satellite Imagery"
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In the decades after Otto Jesse's death in 1901, there were few new insights into the nature of noctilucent clouds.
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Type I veils are very tenuous and lack well-defined structure, somewhat like cirrostratus or poorly defined cirrus.
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satellite to study these noctilucent clouds, which always occur during the summer season near the poles. However,
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Type III billows are arrangements of closely spaced, roughly parallel short streaks that mostly resemble cirrus.
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1187:"Caltech Scientist Proposes Explanation for Puzzling Property of Night-Shining Clouds at the Edge of Space"
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1244:"Comment on 'Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity' by P. M. Bellan"
817:
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Gadsen, M. (OctoberâDecember 1975). "Observations of the colour and polarization of noctilucent clouds".
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of 50° to 65°. They seldom occur at lower latitudes (although there have been sightings as far south as
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1981:
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1898:"Free Access Noctilucent Clouds in Daytime: Circumpolar Particulate Layers Near the Summer Mesopause"
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noctilucent clouds, it is not thought to be a major contributor to the phenomenon as a whole.
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294:, usually at altitudes of 103 to 114 km (338,000 to 374,000 ft). In August 2014, a
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Karlsson, B.; Gumbel, J.; Stegman, J.; Lautier, N.; Murtagh, D.P.; The Odin Team (2004).
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1985:
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analyses of AIM satellite indicate that there is a spatial negative correlation between
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contains very little moisture, approximately one hundred millionth that of air from the
149:, they are visible only when the observer and the lower layers of the atmosphere are in
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2853:
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973:
818:"Noctilucent clouds: What are they and when can you see them? | Royal Observatory"
757:
474:
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117:, detectable as a diffuse scattering layer of water ice crystals near the summer polar
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however it is still possible as NLCs can form at Armagh's latitude within this period.
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Type IV whirls are partial or, more rarely, complete rings of cloud with dark centres.
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These images show measurements of polar mesospheric clouds over the course of one day.
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Noctilucent clouds are first known to have been observed in 1885, two years after the
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3220:
3138:
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1958:
1593:
NASA/Goddard Space Flight Center
Scientific Visualization Studio (10 December 2007).
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clouds may form directly from water vapour in addition to forming on dust particles.
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2826:
2808:
1713:"A mystery solved: Space shuttle shows 1908 Tunguska explosion was caused by comet"
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1407:
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400:, and Stolze and, after that year, continuous observations were carried out at the
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2362:"First Antarctic ground-satellite view of ice aerosol clouds at the edge of space"
17:
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NASA Astronomy
Picture of the Day: Noctilucent Clouds Over Sweden (18 July 2006)
2229:
1746:
946:
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260:
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2026:"NASA balloon captures electric blue clouds during weather forecasting mission"
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632:
508:
317:
264:
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169:
2094:
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1021:
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1993:
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340:). Therefore, they cannot be observed (even if they are present) inside the
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2636:
Time-lapse videos playlist of noctilucent clouds observed in Samara, Russia
2615:
1312:
404:. During this research, the height of the clouds was first determined, via
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1037:(Press release). Naval Research Laboratories. 6 March 2003. Archived from
418:
Noctilucent clouds were first detected from space by an instrument on the
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These clouds may be studied from the ground, from space, and directly by
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are also possibilities. The moisture could be lifted through gaps in the
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2530:"Otto Jesse and the Investigation of Noctilucent Clouds 115 Years Ago"
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at altitudes of around 76 to 85 km (249,000 to 279,000 ft).
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in June 2009 suggests that noctilucent clouds observed following the
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1784:"To Study Night-shining Clouds, NASA Used Its "Super-Soaker" Rocket"
832:"Climate Change Is Responsible for These Rare High-Latitude Clouds"
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CNN Article - Rocket launch prompts calls of strange lights in sky
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and selected species, supplementary features, and other airborne
1896:
Donahue, T. M.; Guenther, B.; Blamont, J. E. (1 September 1972).
1360:. German Commission on History of Geophysics and Cosmical Physics
1060:
11 Aug 2014 SpaceX Falcon 9 caused spectacular noctilucent clouds
1075:
1072:"Study Finds Space Shuttle Exhaust Creates Night-shining Clouds"
1035:"Study Finds Space Shuttle Exhaust Creates Night-Shining Clouds"
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683:
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are not known with certainty. The dust is believed to come from
2644:
3342:
2319:
1743:"Night Time Artificial Cloud Study Using NASA Sounding Rocket"
703:
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220:
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Cumulus castellanus (unofficial alternative name for Cu con))
1622:"NASA Satellite Captures First View of 'Night-Shining Clouds"
495:(CARE) on September 19, 2009, using exhaust particles from a
239:
Noctilucent clouds during arctic dawn seen from high altitude
2498:. International Association of Geomagnetism & Aeronomy.
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of 1908 are evidence that the impact was caused by a comet.
2792:
No differentiated sub-types; tends to resemble cirrostratus
2604:
Southern
Noctilucent Clouds observed at Punta Arenas, Chile
2593:
2583:
2557:
10.1175/1520-0477(2001)082<2457:OJATIO>2.3.CO;2
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10.1175/1520-0469(1972)029<1205:NCIDCP>2.0.CO;2
1189:(Press release). Caltech. 25 September 2008. Archived from
887:"Strange clouds spotted at the edge of Earth's atmosphere"
726:
now recognizes four major forms that can be subdivided.
2337:
10.1175/1520-0493(1933)61<228:NANC>2.0.CO;2
969:"First Mission to Explore Those Wisps in the Night Sky"
1769:"Rocket launch prompts calls of strange lights in sky"
1670:
Kelly, M.C.; C.E. Seyler; M.F. Larsen (22 June 2009).
2114:
2112:
1528:"Studies of Noctilucent Clouds by the Odin Satellite"
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1437:
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Cloud-like phenomena in the upper atmosphere of Earth
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term for Cu con and "Cu cas" is Towering cumulus ))
2210:
Journal of Atmospheric and Solar-Terrestrial Physics
2008:"NASA Balloon Mission Captures Electric Blue Clouds"
926:
Journal of Atmospheric and Solar-Terrestrial Physics
219:
Noctilucent clouds are composed of tiny crystals of
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BBC News Article - Mission to Target Highest Clouds
539:Polar mesospheric clouds illuminated by the rising
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66:
58:
34:
3587:(Mother cloud)+mutatus (e.g. cumulomutatus (cumut)
3584:(Mother cloud)+genitus (e.g. cumulogenitus (cugen)
996:"Appearance of night-shining clouds has increased"
1595:"The First Season of Noctilucent Clouds from AIM"
1358:"On the Diurnal Variation of Noctilucent Clouds"
902:"Mysterious noctilucent clouds span the heavens"
502:suborbital sounding rocket launched from NASA's
153:, but while these very high clouds are still in
2537:Bulletin of the American Meteorological Society
2462:World Meteorological Organization, ed. (2017).
2440:World Meteorological Organization, ed. (2017).
2418:World Meteorological Organization, ed. (2017).
2396:World Meteorological Organization, ed. (2017).
2364:. Australian Antarctic Division. Archived from
1874:World Meteorological Organization, ed. (2017).
1852:World Meteorological Organization, ed. (2017).
1830:World Meteorological Organization, ed. (2017).
1808:World Meteorological Organization, ed. (2017).
145:between ±50° and ±70°. Too faint to be seen in
2631:BBC News - Audio slideshow: Noctilucent clouds
2621:BBC Article - Spacecraft Chases Highest Clouds
2049:Journal of Geophysical Research: Space Physics
1939:Journal of Atmospheric and Terrestrial Physics
1771:. Cable News Network (CNN). 20 September 2009.
1331:"History of Observation of Noctilucent Clouds"
363:reflectivity, in a frequency range of 50
2656:
2442:"Type III Billows, International Cloud Atlas"
1854:"Type III Billows, International Cloud Atlas"
507:news organizations in the United States from
359:Noctilucent clouds are known to exhibit high
8:
2599:Solar Occultation for Ice Experiment (SOFIE)
2088:
2086:
2084:
2082:
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1974:Journal of Geophysical Research: Atmospheres
1213:"Project Studies Night Clouds, Radar Echoes"
1099:
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531:Polar mesospheric clouds over the north pole
125:and from the ground are only visible during
2464:"Type IV Whirls, International Cloud Atlas"
2360:A. Klekociuk; R. Morris; J. French (2008).
1876:"Type IV Whirls, International Cloud Atlas"
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2750:
2705:
2696:
2663:
2649:
2641:
2420:"Type II Bands, International Cloud Atlas"
1832:"Type II Bands, International Cloud Atlas"
1568:"Launch of AIM Aboard a Pegasus XL Rocket"
1324:
1322:
1181:
1179:
857:
855:
853:
851:
458:In the previous year, scientists with the
267:, as well as forming from the reaction of
137:. They are most often observed during the
113:. When viewed from space, they are called
40:
2764:Nacreous polar stratospheric clouds (PSC)
2398:"Type I Veils, International Cloud Atlas"
2335:
2068:
1921:
1810:"Type I Veils, International Cloud Atlas"
1695:
1267:
462:mission had announced their discovery of
408:. That project was discontinued in 1896.
2685:Latin terminology except where indicated
2301:
2299:
157:. Recent studies suggest that increased
2988:Mutatus non-height specific (see below)
1133:
1131:
1129:
1127:
809:
482:United States Naval Research Laboratory
1649:"Mars Clouds Higher Than Any On Earth"
308:The exhaust can be transported to the
168:in Earth's atmosphere, located in the
31:
2594:Noctilucent Cloud Observers' Homepage
962:
960:
958:
956:
864:"Strange Clouds at the Edge of Space"
7:
2528:Schröder, Wilfried (November 2001).
2489:Gadsden, M.; Parviainen, P. (1995).
2274:"Noctilucent clouds from Calar Alto"
2272:Calar Alto Observatory (July 2012).
2176:. Atmospheric Optics. Archived from
1782:Gamilla, Elizabeth (10 March 2021).
1329:Bergman, Jennifer (17 August 2004).
1022:About NLCs, Polar Mesospheric Clouds
301:also caused noctilucent clouds over
3390:Stratocumulus stratiformis (Sc str)
3385:Stratocumulus lenticularis (Sc len)
1902:Journal of the Atmospheric Sciences
1620:O'Carroll, Cynthia (28 June 2007).
1104:Phillips, Tony (19 February 2003).
486:United States Department of Defense
436:Upper Atmosphere Research Satellite
3375:Stratocumulus castellanus (Sc cas)
2931:Cirrocumulus stratiformis (Cc str)
2926:Cirrocumulus lenticularis (Cc len)
1647:SPACE.com staff (28 August 2006).
862:Phillips, Tony (August 25, 2008).
674:Noctilucent clouds may be seen at
493:Charged Aerosol Release Experiment
469:Research published in the journal
25:
3047:Altocumulus stratiformis (Ac str)
3042:Altocumulus lenticularis (Ac len)
2916:Cirrocumulus castellanus (Cc cas)
2308:"Nacreous and Noctilucent Clouds"
771:Aeronomy of Ice in the Mesosphere
724:World Meteorological Organization
453:Aeronomy of Ice in the Mesosphere
245:Aeronomy of Ice in the Mesosphere
133:roughly means "night shining" in
3152:Cumulonimbus capillatus (Cb cap)
3027:Altocumulus castellanus (Ac cas)
2785:polar stratospheric clouds (PSC)
885:Hsu, Jeremy (3 September 2008).
750:
3331:St-only genitus cloud and other
2967:Cirrostratus nebulosus (Cs neb)
1535:35th COSPAR Scientific Assembly
1242:Rapp, M.; Lubken, F.J. (2009).
1156:Cole, Stephen (14 March 2007).
967:Chang, Kenneth (24 July 2007).
380:deposited onto an ice surface.
115:polar mesospheric clouds (PMCs)
3400:Stratocumulus volutus (Sc vol)
3380:Stratocumulus floccus (Sc flo)
3161:Cb-only supplementary features
2962:Cirrostratus fibratus (Cs fib)
1219:: 3. Fall 2003. Archived from
998:. Science Daily. 11 April 2014
591:launched a giant balloon from
1:
3629:Atmospheric optical phenomena
3338:Stratus silvagenitus (St sil)
3196:Cumulonimbus flumen ((Cb flu)
3189:Cb-only accessories and other
3037:Altocumulus lacunosus (Ac la)
2921:Cirrocumulus floccus (Cc flo)
1143:Australian Antarctic Division
1078:. 3 June 2003. Archived from
255:, although particulates from
109:-like phenomena in the upper
3147:Cumulonimbus calvus (Cb cal)
3052:Altocumulus volutus (Ac vol)
3032:Altocumulus floccus (Ac flo)
2726:Noctilucent type III billows
2492:Observing Noctilucent Clouds
2482:General and cited references
1959:10.1016/0021-9169(84)90062-X
1676:Geophysical Research Letters
1485:Geophysical Research Letters
900:Simons, Paul (12 May 2008).
471:Geophysical Research Letters
3101:Nimbostratus virga (Ns vir)
2844:Cirrus castellanus (Ci cas)
2230:10.1016/j.jastp.2010.12.008
947:10.1016/j.jastp.2009.10.007
639:and waveâinduced altitude.
599:which traveled through the
523:Description from satellites
384:Discovery and investigation
3645:
3322:Stratus nebulosus (St neb)
3256:Cumulus congestus (Cu con)
3250:Cumulus mediocris (Cu med)
2885:Cirrus vertebratus (Ci ve)
2729:Noctilucent type IV whirls
2095:"Noctilucent Clouds, NLCs"
1741:NASA (19 September 2009).
1158:"AIM at the Edge of Space"
332:) and wintertime heating (
3179:Cumulonimbus murus ((mur)
3168:Cumulonimbus cauda ((cau)
2859:Cirrus spissatus (Ci spa)
2723:Noctilucent type II bands
2386:Gadsden (1995), pp. 9â10.
2252:The World At Night (TWAN)
1711:Ju, Anne (24 June 2009).
1024:, from Atmospheric optics
788:Polar stratospheric cloud
424:Solar Mesosphere Explorer
390:1883 eruption of Krakatoa
99:Noctilucent clouds (NLCs)
39:
3317:Stratus fractus (St fra)
3245:Cumulus humilis (Cu hum)
3224:Variable vertical extent
3174:Cumulonimbus incus (inc)
2849:Cirrus fibratus (Ci fib)
2720:Noctilucent type I veils
2714:Polar mesospheric clouds
2154:Gadsden (1995), pp.8â10.
1431:Schröder (2001), p. 2464
1387:Schröder (2001), p. 2459
1378:Schröder (2001), p. 2457
184:Noctilucent clouds over
46:Noctilucent clouds over
3395:Stratocumulus Undulatus
2880:Cirrus intortus (Ci in)
2864:Cirrus uncinus (Ci unc)
2854:Cirrus floccus (Ci flo)
1994:10.1029/JD094iD12p14673
1396:Schröder (2001), p.2460
504:Wallops Flight Facility
72:(250,000 to 280,000 ft)
3535:Supplementary features
3415:supplementary features
2350:Gadsden (1995), p. 11.
2312:Monthly Weather Review
2278:Calar Alto Observatory
2130:Annales de GĂ©ophysique
2118:Gadsden (1995), p. 13.
1745:. NASA. Archived from
1597:. NASA. Archived from
1570:. NASA. Archived from
1443:Gadsden (1995), p. 18.
1285:Phys. Chem. Chem. Phys
1160:. NASA. Archived from
1108:. NASA. Archived from
659:
651:Noctilucent clouds in
552:
544:
532:
240:
197:Thomas Romney Robinson
192:
3578:and human-made clouds
3074:Altostratus undulatus
2783:Nitric acid and water
2584:AIM satellite mission
2579:NLC time-lapse movies
2198:Gadsden (1995), p. 8.
2163:Gadsden (1995), p. 9.
650:
550:
538:
530:
432:Utah State University
349:Ultraviolet radiation
238:
183:
164:They are the highest
127:astronomical twilight
2306:Giles, Bill (1933).
2216:(14â15): 2125â2131.
2097:. Atmospheric Optics
2070:10.1002/2017JA024481
2032:. 22 September 2018.
2014:. 20 September 2018.
1980:(D12): 14673â14681.
1788:Smithsonian Magazine
1697:10.1029/2009GL038362
1505:10.1029/2000GL012104
1412:University of Albany
1408:"Noctilucent Clouds"
1356:Schröder, Wilfried.
1269:10.1029/2008JD011323
1193:on 29 September 2008
1145:. 28 September 2020.
1139:"Noctilucent clouds"
1041:on 17 September 2008
874:on February 1, 2010.
834:. Smithsonian. 2018.
491:(STP) conducted the
288:Solid Rocket Booster
103:night shining clouds
3596:Homomutatus (homut)
3592:Homogenitus (hogen)
3562:Praecipitatio (pra)
2774:Lenticular nacreous
2549:2001BAMS...82.2457S
2368:on 25 February 2012
2328:1933MWRv...61..228H
2222:2011JASTP..73.2125H
2142:1975AnG....31..507G
2061:2018JGRA..123..955H
1986:1989JGR....9414673T
1951:1984JATP...46..819T
1914:1972JAtS...29.1205D
1688:2009GeoRL..3614103K
1547:2004cosp...35.1921K
1497:2001GeoRL..28..971H
1297:2005PCCP....7.3970M
1260:2009JGRD..11411204R
1164:on 27 November 2016
1082:on 27 November 2016
939:2010JASTP..72...51M
798:Twilight phenomenon
622:weather forecasting
159:atmospheric methane
111:atmosphere of Earth
3358:Stratocumulus (Sc)
3345:(Fg) Surface level
3286:Trade wind cumulus
2771:Cirriform nacreous
2609:2020-08-05 at the
2515:on 31 October 2008
2322:Weather: 228â229.
1749:on 27 October 2009
1721:Cornell University
1628:on 20 October 2008
1248:Geophys. Res. Lett
1112:on 12 October 2008
660:
553:
545:
533:
489:Space Test Program
402:Berlin Observatory
259:and dust from the
241:
193:
121:. They consist of
70:76,000 to 85,000 m
35:Noctilucent clouds
18:Noctilucent clouds
3611:
3610:
3607:
3606:
3603:
3602:
3521:Translucidus (tr)
3475:
3474:
3408:
3407:
3352:
3351:
3294:
3293:
3215:
3214:
3131:Towering vertical
3128:Cumulonimbus (Cb)
3113:
3112:
3109:
3108:
3084:Nimbostratus (Ns)
3060:
3059:
2995:
2994:
2975:
2974:
2945:Cirrostratus (Cs)
2939:
2938:
2899:Cirrocumulus (Cc)
2893:
2892:
2873:Ci-only varieties
2803:
2802:
2799:
2798:
2740:
2739:
2736:
2735:
2543:(11): 2457â2468.
2505:978-0-9650686-0-4
1717:Cornell Chronicle
1291:(23): 3970â3979.
778:Cloud iridescence
338:adiabatic heating
330:adiabatic cooling
282:The exhaust from
273:hydroxyl radicals
96:
95:
16:(Redirected from
3636:
3486:
3466:Actinoform cloud
3363:
3305:
3228:
3202:Overshooting top
3135:
3124:
3091:
3066:Altostratus (As)
3015:
3010:Altocumulus (Ac)
3006:
2950:
2904:
2832:
2823:
2814:
2760:
2751:
2706:
2697:
2665:
2658:
2651:
2642:
2567:
2565:
2563:
2534:
2524:
2522:
2520:
2514:
2508:. Archived from
2497:
2475:
2474:
2472:
2470:
2459:
2453:
2452:
2450:
2448:
2437:
2431:
2430:
2428:
2426:
2415:
2409:
2408:
2406:
2404:
2393:
2387:
2384:
2378:
2377:
2375:
2373:
2357:
2351:
2348:
2342:
2341:
2339:
2303:
2294:
2293:
2291:
2289:
2280:. Archived from
2269:
2263:
2262:
2260:
2258:
2246:(13 July 2008).
2240:
2234:
2233:
2205:
2199:
2196:
2190:
2189:
2187:
2185:
2180:on 4 August 2008
2170:
2164:
2161:
2155:
2152:
2146:
2145:
2125:
2119:
2116:
2107:
2106:
2104:
2102:
2090:
2075:
2074:
2072:
2040:
2034:
2033:
2022:
2016:
2015:
2004:
1998:
1997:
1969:
1963:
1962:
1934:
1928:
1927:
1925:
1908:(6): 1205â1209.
1893:
1887:
1886:
1884:
1882:
1871:
1865:
1864:
1862:
1860:
1849:
1843:
1842:
1840:
1838:
1827:
1821:
1820:
1818:
1816:
1805:
1799:
1798:
1796:
1794:
1779:
1773:
1772:
1765:
1759:
1758:
1756:
1754:
1738:
1732:
1731:
1729:
1727:
1708:
1702:
1701:
1699:
1667:
1661:
1660:
1658:
1656:
1644:
1638:
1637:
1635:
1633:
1624:. Archived from
1617:
1611:
1610:
1608:
1606:
1590:
1584:
1583:
1581:
1579:
1574:on 16 March 2010
1564:
1558:
1557:
1555:
1553:
1532:
1523:
1517:
1516:
1479:
1473:
1472:
1470:
1469:
1460:. Archived from
1450:
1444:
1441:
1432:
1429:
1423:
1422:
1420:
1418:
1403:
1397:
1394:
1388:
1385:
1379:
1376:
1370:
1369:
1367:
1365:
1353:
1347:
1346:
1344:
1342:
1333:. Archived from
1326:
1317:
1316:
1305:10.1039/b508846a
1280:
1274:
1273:
1271:
1239:
1233:
1232:
1230:
1228:
1209:
1203:
1202:
1200:
1198:
1183:
1174:
1173:
1171:
1169:
1153:
1147:
1146:
1135:
1122:
1121:
1119:
1117:
1106:"Strange Clouds"
1101:
1092:
1091:
1089:
1087:
1068:
1062:
1057:
1051:
1050:
1048:
1046:
1031:
1025:
1019:
1008:
1007:
1005:
1003:
992:
986:
985:
983:
981:
964:
951:
950:
920:
914:
913:
911:
909:
897:
891:
890:
882:
876:
875:
870:. Archived from
859:
846:
842:
836:
835:
828:
822:
821:
814:
783:Iridescent cloud
760:
755:
754:
587:On 8 July 2018,
305:after a launch.
303:Orlando, Florida
249:upper atmosphere
44:
32:
21:
3644:
3643:
3639:
3638:
3637:
3635:
3634:
3633:
3614:
3613:
3612:
3599:
3588:
3577:
3571:
3542:Asperitas (asp)
3530:
3511:Perlucidus (pe)
3496:Duplicatus (du)
3481:
3471:
3468:(Stratocumulus)
3441:accessory cloud
3439:
3433:
3414:
3404:
3348:
3326:
3290:
3269:
3223:
3211:
3184:
3156:
3130:
3119:
3105:
3086:
3078:
3056:
3001:
2991:
2981:
2980:High-level-only
2971:
2935:
2889:
2868:
2818:
2795:
2784:
2777:
2755:
2754:Very high-level
2732:
2713:
2701:
2686:
2669:
2611:Wayback Machine
2575:
2570:
2561:
2559:
2532:
2527:
2518:
2516:
2512:
2506:
2495:
2488:
2484:
2479:
2478:
2468:
2466:
2461:
2460:
2456:
2446:
2444:
2439:
2438:
2434:
2424:
2422:
2417:
2416:
2412:
2402:
2400:
2395:
2394:
2390:
2385:
2381:
2371:
2369:
2359:
2358:
2354:
2349:
2345:
2305:
2304:
2297:
2287:
2285:
2284:on 25 July 2014
2271:
2270:
2266:
2256:
2254:
2242:
2241:
2237:
2207:
2206:
2202:
2197:
2193:
2183:
2181:
2174:"Rocket Trails"
2172:
2171:
2167:
2162:
2158:
2153:
2149:
2127:
2126:
2122:
2117:
2110:
2100:
2098:
2092:
2091:
2078:
2042:
2041:
2037:
2024:
2023:
2019:
2006:
2005:
2001:
1971:
1970:
1966:
1936:
1935:
1931:
1895:
1894:
1890:
1880:
1878:
1873:
1872:
1868:
1858:
1856:
1851:
1850:
1846:
1836:
1834:
1829:
1828:
1824:
1814:
1812:
1807:
1806:
1802:
1792:
1790:
1781:
1780:
1776:
1767:
1766:
1762:
1752:
1750:
1740:
1739:
1735:
1725:
1723:
1710:
1709:
1705:
1669:
1668:
1664:
1654:
1652:
1646:
1645:
1641:
1631:
1629:
1619:
1618:
1614:
1604:
1602:
1601:on 15 July 2019
1592:
1591:
1587:
1577:
1575:
1566:
1565:
1561:
1551:
1549:
1530:
1525:
1524:
1520:
1481:
1480:
1476:
1467:
1465:
1452:
1451:
1447:
1442:
1435:
1430:
1426:
1416:
1414:
1405:
1404:
1400:
1395:
1391:
1386:
1382:
1377:
1373:
1363:
1361:
1355:
1354:
1350:
1340:
1338:
1337:on 28 June 2009
1328:
1327:
1320:
1282:
1281:
1277:
1254:(D11): D11204.
1241:
1240:
1236:
1226:
1224:
1223:on 19 July 2016
1211:
1210:
1206:
1196:
1194:
1185:
1184:
1177:
1167:
1165:
1155:
1154:
1150:
1137:
1136:
1125:
1115:
1113:
1103:
1102:
1095:
1085:
1083:
1070:
1069:
1065:
1058:
1054:
1044:
1042:
1033:
1032:
1028:
1020:
1011:
1001:
999:
994:
993:
989:
979:
977:
966:
965:
954:
922:
921:
917:
907:
905:
899:
898:
894:
884:
883:
879:
861:
860:
849:
843:
839:
830:
829:
825:
816:
815:
811:
806:
793:Space jellyfish
756:
749:
746:
719:
711:sounding rocket
645:
558:summer solstice
525:
386:
356:not yet known.
223:up to 100
217:
178:
71:
54:
28:
23:
22:
15:
12:
11:
5:
3642:
3640:
3632:
3631:
3626:
3616:
3615:
3609:
3608:
3605:
3604:
3601:
3600:
3598:
3597:
3594:
3589:
3585:
3581:
3579:
3576:Mother clouds
3573:
3572:
3570:
3569:
3564:
3559:
3554:
3549:
3544:
3538:
3536:
3532:
3531:
3529:
3528:
3526:Undulatus (un)
3523:
3518:
3513:
3508:
3503:
3501:Lacunosus (la)
3498:
3492:
3490:
3483:
3477:
3476:
3473:
3472:
3470:
3469:
3462:
3457:
3452:
3446:
3444:
3438:Low-level-only
3435:
3434:
3432:
3431:
3425:
3418:
3416:
3413:Low-level-only
3410:
3409:
3406:
3405:
3403:
3402:
3397:
3392:
3387:
3382:
3377:
3371:
3369:
3360:
3354:
3353:
3350:
3349:
3347:
3346:
3340:
3334:
3332:
3328:
3327:
3325:
3324:
3319:
3313:
3311:
3302:
3296:
3295:
3292:
3291:
3289:
3288:
3283:
3277:
3275:
3271:
3270:
3268:
3267:
3252:
3247:
3242:
3236:
3234:
3225:
3217:
3216:
3213:
3212:
3210:
3209:
3204:
3199:
3192:
3190:
3186:
3185:
3183:
3182:
3176:
3171:
3164:
3162:
3158:
3157:
3155:
3154:
3149:
3143:
3141:
3132:
3121:
3115:
3114:
3111:
3110:
3107:
3106:
3104:
3103:
3097:
3095:
3088:
3080:
3079:
3077:
3076:
3070:
3068:
3062:
3061:
3058:
3057:
3055:
3054:
3049:
3044:
3039:
3034:
3029:
3023:
3021:
3012:
3003:
2997:
2996:
2993:
2992:
2990:
2989:
2985:
2983:
2977:
2976:
2973:
2972:
2970:
2969:
2964:
2958:
2956:
2947:
2941:
2940:
2937:
2936:
2934:
2933:
2928:
2923:
2918:
2912:
2910:
2901:
2895:
2894:
2891:
2890:
2888:
2887:
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2248:"NLC Surprise"
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2055:(1): 955â973.
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475:Tunguska Event
464:carbon dioxide
446:Odin satellite
385:
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284:Space Shuttles
243:Data from the
216:
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151:Earth's shadow
105:, are tenuous
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2743:
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2700:Extreme-level
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2093:Cowley, Les.
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1464:on 2012-09-20
1463:
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1409:
1406:Keesee, Bob.
1402:
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669:cirrus clouds
665:
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618:gravity waves
614:
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513:Massachusetts
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441:In 2001, the
439:
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429:
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416:
414:
409:
407:
406:triangulation
403:
399:
395:
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342:Polar circles
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88:Precipitation
85:
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61:
57:
53:
49:
43:
38:
33:
30:
19:
3460:Pannus (pan)
3450:Pileus (pil)
3422:Arcus ((arc)
3300:Stratus (St)
3221:Cumulus (Cu)
3198:Beaver tail)
3000:Medium-level
2809:Tropospheric
2709:
2679:hydrometeors
2560:. Retrieved
2540:
2536:
2517:. Retrieved
2510:the original
2491:
2467:. Retrieved
2457:
2445:. Retrieved
2435:
2423:. Retrieved
2413:
2401:. Retrieved
2391:
2382:
2370:. Retrieved
2366:the original
2355:
2346:
2315:
2311:
2286:. Retrieved
2282:the original
2277:
2267:
2255:. Retrieved
2251:
2238:
2213:
2209:
2203:
2194:
2182:. Retrieved
2178:the original
2168:
2159:
2150:
2133:
2129:
2123:
2099:. Retrieved
2052:
2048:
2038:
2029:
2020:
2011:
2002:
1977:
1973:
1967:
1942:
1938:
1932:
1905:
1901:
1891:
1879:. Retrieved
1869:
1857:. Retrieved
1847:
1835:. Retrieved
1825:
1813:. Retrieved
1803:
1791:. Retrieved
1787:
1777:
1763:
1753:20 September
1751:. Retrieved
1747:the original
1736:
1724:. Retrieved
1716:
1706:
1679:
1675:
1665:
1653:. Retrieved
1642:
1630:. Retrieved
1626:the original
1615:
1603:. Retrieved
1599:the original
1588:
1576:. Retrieved
1572:the original
1562:
1550:. Retrieved
1538:
1534:
1521:
1488:
1484:
1477:
1466:. Retrieved
1462:the original
1457:
1448:
1427:
1415:. Retrieved
1401:
1392:
1383:
1374:
1362:. Retrieved
1351:
1339:. Retrieved
1335:the original
1288:
1284:
1278:
1251:
1247:
1237:
1225:. Retrieved
1221:the original
1216:
1207:
1195:. Retrieved
1191:the original
1166:. Retrieved
1162:the original
1151:
1114:. Retrieved
1110:the original
1084:. Retrieved
1080:the original
1066:
1055:
1043:. Retrieved
1039:the original
1029:
1000:. Retrieved
990:
978:. Retrieved
972:
933:(1): 51â61.
930:
924:
918:
906:. Retrieved
895:
889:. USA Today.
880:
872:the original
840:
826:
812:
720:
708:
673:
661:
626:
601:stratosphere
586:
582:
578:
574:
570:
566:
562:
554:
517:
479:
470:
468:
460:Mars Express
457:
450:
440:
417:
410:
387:
377:micrometeors
358:
347:
315:
307:
292:thermosphere
281:
277:stratosphere
253:micrometeors
242:
218:
194:
163:
141:months from
130:
123:ice crystals
114:
102:
98:
97:
59:Abbreviation
29:
3624:Cloud types
3567:Virga (vir)
3557:Mamma (mam)
3547:Cavum (cav)
3506:Opacus (op)
3455:Velum (vel)
3428:Tuba ((tub)
3181:Wall cloud)
3170:Tail cloud)
3087:Multi-level
2827:Cirrus (Ci)
2710:Noctilucent
2692:Mesospheric
2136:: 507â516.
1651:. SPACE.com
643:Observation
633:tomographic
607:to Western
603:across the
497:Black Brant
430:in 1995 at
353:solar cycle
334:downwelling
261:troposphere
230:mesospheric
205:Chelyabinsk
131:Noctilucent
3618:Categories
3480:Non-height
2817:High-level
2562:18 October
2519:16 October
2372:19 October
2244:Tunç Tezel
2184:19 October
2101:18 October
1655:19 October
1605:19 October
1578:19 October
1552:16 October
1468:2009-07-27
1417:19 October
1227:19 October
1197:19 October
1045:19 October
627:NASA uses
509:New Jersey
318:mesosphere
265:tropopause
170:mesosphere
3489:Varieties
3443:and other
3281:Horseshoe
3207:Hot tower
3118:Low-level
3094:Varieties
1632:6 October
1454:"Welcome"
1364:6 October
1341:6 October
1168:6 October
1116:5 October
1086:5 October
980:5 October
908:6 October
804:Citations
676:latitudes
451:The AIM (
438:in 2001.
326:upwelling
257:volcanoes
221:water ice
215:Formation
143:latitudes
119:mesopause
3482:specific
2756:15â30 km
2702:80â85 km
2607:Archived
1793:11 March
1541:: 1921.
1313:19810327
1217:ECE News
766:Aeronomy
744:See also
700:twilight
653:Buryatia
398:Foerster
299:Falcon 9
155:sunlight
147:daylight
67:Altitude
3464:Other-
3367:Species
3309:Species
3240:Fractus
3232:Species
3139:Species
3019:Species
2954:Species
2908:Species
2836:Species
2819:3â18 km
2545:Bibcode
2469:18 July
2447:18 July
2425:18 July
2403:18 July
2324:Bibcode
2288:17 July
2257:17 July
2218:Bibcode
2138:Bibcode
2057:Bibcode
1982:Bibcode
1947:Bibcode
1910:Bibcode
1881:18 July
1859:18 July
1837:18 July
1815:18 July
1726:25 June
1684:Bibcode
1543:Bibcode
1513:9335046
1493:Bibcode
1458:agu.org
1293:Bibcode
1256:Bibcode
935:Bibcode
609:Nunavut
593:Esrange
443:Swedish
413:Wegener
394:Germany
316:As the
275:in the
269:methane
186:Uppsala
176:General
62:NLC/PMC
52:Germany
3424:Shelf)
3120:0â2 km
3002:2â8 km
2675:genera
2502:
1511:
1311:
692:Turkey
657:Russia
637:albedo
613:Canada
605:Arctic
597:Sweden
369:sodium
322:Sahara
310:Arctic
296:SpaceX
209:bolide
201:Armagh
190:Sweden
166:clouds
139:summer
3274:Other
2712:(NLC)
2672:Cloud
2533:(PDF)
2513:(PDF)
2496:(PDF)
2318:(8).
2030:TECH2
1531:(PDF)
1509:S2CID
1002:7 May
717:Forms
696:Spain
688:Italy
680:Paris
664:ozone
428:lidar
361:radar
271:with
207:super
135:Latin
107:cloud
101:, or
82:Other
48:Laboe
3264:ICAO
2564:2008
2521:2008
2500:ISBN
2471:2019
2449:2019
2427:2019
2405:2019
2374:2008
2290:2014
2259:2014
2186:2008
2103:2008
2012:NASA
1883:2019
1861:2019
1839:2019
1817:2019
1795:2021
1755:2009
1728:2009
1657:2008
1634:2008
1607:2008
1580:2008
1554:2008
1419:2008
1366:2008
1343:2008
1309:PMID
1229:2008
1199:2008
1170:2008
1118:2008
1088:2008
1076:NASA
1047:2008
1004:2014
982:2008
910:2008
868:NASA
694:and
684:Utah
589:NASA
480:The
373:iron
371:and
336:and
328:and
3343:Fog
2683:WMO
2553:doi
2332:doi
2320:BBC
2226:doi
2065:doi
2053:123
1990:doi
1955:doi
1918:doi
1692:doi
1501:doi
1301:doi
1264:doi
1252:114
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