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A rare display of Noctilucent clounds in the northern sky from Pitt Meadows BC. Noctilucent clouds are the highest clouds in the atmosphere, forming above 75km and are usually seen just in the summer months at 50 to 70 degrees latitude (north or south) They are very faint, only seen when lit by the sun from over the horizon, when the sky is almost dark. Timelapse sequence uses 1 second exposures, at roughly 1 minute intervals for 15 minutes. F5.6, 55mm, ISO800. Canon T1i DSLR. Music Credit: Diversion Voice - Red River ( Clinical Archives Mix ) / CC BY-NC-ND 3.0 Source: https://www.flickr.com/photos/44089209@N08/5892912691 Uploader: https://www.flickr.com/photos/suraky/

View of noctilucent clouds moving higher as twilight brightens, approximately 2:28-2:49am MDT on July 1st, 2017 Source: https://www.flickr.com/photos/55702966@N05/34850079333 Uploader: Jeff Wallace

Climatology of noctilucent clouds based on U.S.S.R. observations during IGY

Analysis of synoptic meteorological maps for noctilucent clouds over western Siberia

Analysis of synoptic meteorological maps for noctilucent clouds over western Siberia

A review is made of the existing concepts of the constitution or origin of the clouds, and a mechanism is suggested which might explain their apparent dependence on latitude. Their frequency of occurrence with respect to latitude, longitude, time of year, and other factors, is analyzed in detail. Year-by-year changes in the number of occurrences are considered in relation to the '11-year' sunspot cycle. A comprehensive sample of data on cloud movement is summarized, although in view of the highly complicated field of motion in noctilucent clouds, this subject is difficult to treat satisfactorily. A comparison is made of rocket samples of particle size and concentration with values deduced from polarization measurements.

I took 90 10 second exposure photos of the noctilucent cloud display as seen from the side of a road. Occasional cars go past and by the end my camera lens had started to fog up. Source: https://www.flickr.com/photos/53575715@N02/8992245524 Uploader: https://www.flickr.com/photos/astronomyblog/

Statistical analysis on noctilucent cloud occurrence with synoptic meteorological and ionospheric conditions in Siberia

The method for the determination of the optical density of tropospheric and mesospheric aerosols and for the estimation of the scattering phase function in the forward directions (0 to 30 deg) is proposed. The method is based on measurements of the brightness of the twilight horizon with the high resolution limb camera having five separated fields of view. In some detail the features of the camera are described and the mathematical aspects of remote sensing data inversion are discussed.

The Aeronomy of Ice in the Mesosphere (AIM) mission is the first satellite dedicated to the study of noctilucent clouds. Noctilucent clouds, sometimes called Polar Mesospheric Clouds, were first reported in 1885. Forming at altitudes above 50 miles, they are so faint that they can only be seen from the ground in the reflected light of the Sun after it has set below the horizon. Since their discovery, their cause has been a subject of study as a possible indicator of climate change. For those interested in observing noctilucent clouds from the ground, there are images and information at SpaceWeather's

Two types of fundamental topological junctions of elements are deduced from a nonlinear thermodynamical model. Using this scheme, the possibility of a causal relation between fireballs and faint meteors as nonlinear sources on the one hand, and noctilucent clouds (NC) and Hoffmeister's enhanced airglow (EA) as complementary formative processes in the middle atmosphere and ionosphere, on the other hand, is examined. The principal role of the global atmospheric circulation in this relation is demonstrated. Such circulation in the mesosphere appears to prevent the neutral dust dissipated by fireballs from becoming an efficient agent in NLC generation. In this case, the behavior of ionized material deposited by both the bright and faint meteors is more probably controlled, as shown from the annual variation of the E sub s layer by the darkness of lunar eclipses and the global circulation of the lower thermosphere. The role of fireballs and neutral dust might be more significant as a source of EA phenomenon.

THE VISIBLE COLOR AND TRUE COLOR OF THREE BRIGHT SECTIONS OF NOCTILUCENT CLOUDS, ALONG WITH THE CLOUDLESS SKY BACKGROUND ADJACENT TO IT WAS MEASURED USING A ROSENBERG ASTROPHOTOMETER. RESULTS SHOW THAT THE DIFFUSED COLOR OF THE CLOUD IS CLOSE TO BOTH THE COLOR OF A CLEAR DAYTIME SKY (BLUE) AND THAT OF DIFFUSE COLOR ACCORDING TO RAYLEIGH'S LAW. DETAILED RESULTS ARE GIVEN IN A GRAPH.

At high latitudes in the summer months, iridescent clouds form some 80 kilometers (50 miles) above the surface of the Earth. Their high altitude allows them to reflect sunlight after the Sun has set. These night-shining, or noctilucent, clouds long puzzled the researchers who studied them, who wondered how they formed. The clouds' behavior grew even more mysterious over the past two decades as the clouds began to shine more brightly and appear at lower latitudes than they did before. The first satellite designed to study noctilucent clouds, NASA's Aeronomy of Ice in the Mesosphere www.nasa.gov/mission_pages/aim/index.html (AIM) mission released the first view of these clouds over the entire Northern Hemisphere in 2007, at a resolution of approximately 5 kilometers (3 miles). This image, acquired on June 11, 2007, shows some of the first data AIM collected about these clouds. In this image, centered on the North Pole, white indicates clouds with the greatest density of ice particles, and dark blue indicates clouds with the lowest. Because ice particles reflect sunlight, a greater concentration of such particles creates a higher albedo -- the ratio of reflected light to total incoming light. Areas of no data appear in black, and landmass outlines appear in blue-green. Noctilucent clouds, also known as polar mesospheric clouds, form in a part of the atmosphere roughly 50 to 86 kilometers (30 to 54 miles) above the surface of our planet. In the months following AIM's early observations, researchers working with the satellite shared some of their findings. They discovered that the clouds appear daily, are widespread, and vary on an hourly to daily basis. They also found that the clouds' brightness varies over horizontal scales of about 3 kilometers (2 miles). To their surprise, the researchers also noticed that the ice in the mesosphere -- the layer of the atmosphere where the clouds form -- occurs in a single, continuous layer stretching from about 82 to 89 kilometers (51 to 55 miles) above the Earth's surface. By late 2007, AIM had documented the life cycle of noctilucent clouds in the Northern Hemisphere, noting that they first appeared around May 25 and lasted through late August. Although AIM had provided researchers with valuable information on noctilucent clouds by the end of the year, many other questions remained, and the researchers planned to keep watching AIM's progress over the life of the mission. O'Carroll, C. (2007, June 28). www.nasa.gov/mission_pages/aim/multimedia/first_view.html NASA Satellite Captures First View of ''Night-Shining Clouds.'' Accessed January 4, 2008. O'Carroll, C., Steigerwald, B. (2007, December 10). www.nasa.gov/mission_pages/aim/mystery_clouds.html NASA Satellite Reveals Unprecedented View of Mysterious ''Night-Shining'' Clouds. Accessed January 4, 2008. Image courtesy Cloud Imaging and Particle Size Experiment data processing team at the University of Colorado Laboratory for Atmospheric and Space Physics. Text by Michon Scott.

OBSERVATIONAL DATA ON NOCTILUCENT CLOUDS ARE PRESENTED, INCLUDING GEOGRAPHIC DISTRIBUTION, SEASONAL FREQUENCIES, DURATION, CIRCUMSTANCES FOR MOVEMENT, AND PARTICLE MEASUREMENT. THEORETICAL CONCEPTS ARE ALSO CONSIDERED, EMPHASIZING VOLCANIC RELATIONSHIP AND INTRUSIONS OF COSMIC DUST.

I shot this friday night on a ridge near Twelvemile Summit, about 3 miles down the Fairbanks-Circle Historic Trail. There were some strong aurora that barely showed through the twilight, and a beautiful display of noctilucent (night shining) clouds. I've never shot a timelapse with a flash before but it made a cool way to have stable light on some part of the scene while the skylight changed over the course of the night. Set the flash, set the camera ISO and lens aperture for the flash, then use the shutter speed to follow the skylight. I intended to make a steady transition from evening-night-morning but a few times I fell asleep and waited too long to change shutter speed, so the jump was too big to smooth out in post. 2x Nikon D610s and 1x Nikon D810, 24mm Rokinon tilt/shift, 24mm sigma f/1.8, 50mm Nikkon f/1.2. The music is a selection from Com(?) by Mono. Source: https://www.flickr.com/photos/37564545@N04/20017095433 Uploader: Jason Ahrns

Noctilucent cloud observations at Novosibirsk Youth Astronomical Observatory in Soviet Union

Noctilucent clouds forming over Vuosaari, Helsinki, Finland. Time lapse taken between 00:00-03:00. Source: https://www.flickr.com/photos/19935963@N00/14735413973 Uploader: Timo Newton-Syms

NUMEROUS ADVANTAGES TO INVESTIGATING NOCTILUCENT CLOUDS FROM AN ORBITING SPACECRAFT RATHER THAN FROM GROUND STATIONS ARE PRESENTED. THE GEOMETRICAL RELATIONSHIPS INVOLVED IN SUCH OBSERVATIONS AND THEIR EFFECT ON THE OBSERVATIONS ARE DISCUSSED. EXAMPLES OF NOCTILUCENT CLOUD OBSERVATION DURING SOYUZ 9 FLIGHT ARE INCLUDED.

I haven't uploaded anything in a while - have some noctilucent (night-shining) clouds from 3 weeks ago. I has more timelapses if you like this one. Source: https://www.flickr.com/photos/37564545@N04/7912269272 Uploader: Jason Ahrns

Alan Watt CTTM LIVE on RBN 53 HAARPing On About New Noctilucent Clouds Illuminating Your Night Dec 19, 2007 Dec. 19, 2007 Alan Watt "Cutting Through The Matrix" LIVE on RBN: Title Copyright Alan Watt Dec. 19, 2007: "HAARPing on about New Noctilucent Clouds Illuminating Your Night - Brought to You by NASA's Nocturnal E-Missions Public Relations Staff" © Alan Watt Dec. 19, 2007

Alan Watt CTTM LIVE on RBN 53 HAARPing On About New Noctilucent Clouds Illuminating Your Night Dec 19, 2007 Dec. 19, 2007 Alan Watt "Cutting Through The Matrix" LIVE on RBN: Title Copyright Alan Watt Dec. 19, 2007: "HAARPing on about New Noctilucent Clouds Illuminating Your Night - Brought to You by NASA's Nocturnal E-Missions Public Relations Staff" © Alan Watt Dec. 19, 2007

Structural formation analysis on noctilucent clouds

IT IS SHOWN BY THE EXAMPLE OF SELECTED OBSERVATIONS THAT A RELATIONSHIP EXISTS BETWEEN MESOSPHERIC CIRCULATION (FAUST'S MODEL) AND THE FREQUENCY OF NOCTILUCENT CLOUDS. THE PREREQUISITE FOR THE FORMATION OF NOCTILUCENT CLOUDS ARE LOW TEMPERATURES AND OTHER COMPONENTS SUCH AS, SUFFICIENT H2O CONDITIONS. DURING THE WINTER CIRCULATION (DESCENDING MOTION ACCORDING TO FAUST'S MODEL), NO NOCTILUCENT CLOUDS CAN BE OBSERVED.

The Aeronomy of Ice in the Mesosphere (AIM) mission will provide the first detailed exploration of Earth's unique and elusive noctilucent or night shining clouds that are found literally on the "edge of space". Located near the top of the Earth's mesosphere (the region just above the stratosphere), very little is known about how these polar mesospheric clouds form or why they vary. They are being seen at lower latitudes than ever before and have been growing brighter and more frequent, leading some scientists to suggest that this recent increase may be the direct result of human-induced climate change. The mission is led by Dr. James Russell of the Center for Atmospheric Sciences at Hampton University.Music by

The study of noctilucent clouds (NLC) is one century old, yet the origin and nature of these clouds is still uncertain. It is known that these clouds form in the cold, high latitude summer mesopause region where temperatures can approach 110K. Their association with the very cold air in this region supports the theory that they consist of water ice particles. It has been suggested that NLC are anticorrelated with aurorae since aurorally induced effects at or near the mesopause may lead to processes which retard or altogether inhibit NLC formation. This study will review some general characteristics of NLC, polar mesospheric clouds (PMC) and aurorae and then discuss several ways in which aurorae may interact with these clouds.

We conclude from our experiments that the ice particles present in noctilucent clouds may often exhibit cubic habit. It appears even possible that high tropospheric ice crystals may occasionally exhibit such habit. That would be consistent with rare, but reliable observations of the Scheiner's halo. In the case of noctilucent clouds, however, it is doubtful that the crystal habit is after all of much practical importance, because due to low growth rates and limited duration of supersaturation at the mesopause, the crystals must be very small. Ice crystals of dimensions much smaller than the wavelength of transmitted electromagnetic waves interact with the waves as Rayleigh scatterers, which allows for fairly simple theoretical treatments of the interactions. No refraction or surface reflection would be occurring. It appears that even after a few days of growth noctilucent cloud particles are still only a fraction of a micron in diameter. That is less than or equivalent to the wavelength of visible light.

Credit: Jean-Luc Dauvergne Details: https://apod.nasa.gov/apod/ap180710.html Source: https://www.youtube.com/watch?v=8i8-IuYoz24 Uploader: APOD Videos

Noctilucent cloud observations

The sliver of the setting moon and clouds that shine at night -- noctilucent clouds -- caught the eye of astronaut Ed Lu aboard the International Space Station (ISS) last week. Noctilucent clouds are very high clouds that look like cirrus clouds, but are much higher (75-90 km above the Earth's surface) than clouds that we observe every day. They are optically thin and can only be observed during twilight hours, when the sun is just below the horizon and only shines on the uppermost atmosphere. In this image, the limb of the Earth at the bottom transitions into the orange-colored troposphere, the lowest and most dense portion of the Earth's atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue- colored atmosphere. The silvery-blue noctilucent clouds are far above this boundary. This image was taken July 27, 2003 when the ISS was over central Asia. June and July is the season for noctilucent clouds in the northern hemisphere -- they form in the polar mesosphere, generally above 50 degrees latitude. Recent studies address why noctilucent clouds exist, whether the frequency of occurrence has increased throughout the 20th century (some researchers believe they have), and whether their frequency reflects human activities. Astronauts and cosmonauts have observed them over northern latitudes (Europe, Russia) in the past, but this summer's display has been remarkable. Zahn, U. , Are Noctilucent Clouds Truly a ''Miner's Canary'' for Global Change?, Eos, Vol. 84, No. 28, July 15, 2003

Glowing electric-blue at the edge of space, noctilucent clouds have surprised researchers by appearing early this year. The unexpected apparition hints at a change in the "teleconnections" of Earth's atmosphere.

Evaluation of rocket soundings of noctilucent clouds in upper atmosphere

Observation of noctilucent clouds from earth surface and from spacecraft

Atmospheric dynamics in upper atmosphere and noctilucent clouds

Spatial coordinates of noctilucent clouds from photographic measurement of cloud details and reference star positions

Light ray refraction and absorption observed in noctilucent clouds

Alan Watt CTTM LIVE on RBN 53 HAARPing On About New Noctilucent Clouds Illuminating Your Night Dec 19, 2007 Dec. 19, 2007 Alan Watt "Cutting Through The Matrix" LIVE on RBN: Title Copyright Alan Watt Dec. 19, 2007: "HAARPing on about New Noctilucent Clouds Illuminating Your Night - Brought to You by NASA's Nocturnal E-Missions Public Relations Staff" © Alan Watt Dec. 19, 2007

Nessie and Noctilucent Clouds: A Meteorological Explanation for Some Loch Ness Monster Sightings

This report results from a contract tasking University of East Anglia as follows: The Grantee will investigate the kinetics of atomic Na and K uptake on both amorphous and cubic crystalline ice films, over the temperature range 100 to 150 K. The data obtained will be used in a predictive, high resolution 1-dimensional model of the upper mesosphere. Model predictions will be validated by comparison with lidar observations of the depletion of Na and K layers during the formation of noctiluscent clouds. The results of the kinetic studies and model validation will then be published and will be provided to AFRL personnel for inclusion in mesospheric background codes.

NOCTILUCENT CLOUDS WITH WAVE MOVEMENT, CHEMICAL COMPOSITION, AND WATER VAPOR

Acoustic grenade soundings to determine relation between temperature structure in atmosphere and occurrence of noctilucent clouds

Acoustic grenade soundings to determine relation between temperature structure in atmosphere and occurrence of noctilucent clouds

The purpose of this project was to develop rocket-borne probes to detect charged aerosol layers in the mesosphere. These include sporadic E layers, which have their origin in meteoric dust, and noctilucent clouds, which form in the arctic summer and are composed of ice crystals. The probe being developed consists of a charge collecting patch connected to a sensitive electrometer which measures the charge deposited on the patch by impacting aerosols. The ambient electrons and light ions in the mesosphere are prevented from being collected by a magnetic field. The magnetic force causes these lighter particles to turn so that they miss the collecting patch.

The purpose of this project was to develop rocket-borne probes to detect charged aerosol layers in the mesosphere. These include sporadic E layers, which have their origin in meteoric dust, and noctilucent clouds, which form in the arctic summer and are composed of ice crystals. The probe being developed consists of a charge collecting patch connected to a sensitive electrometer which measures the charge deposited on the patch by impacting aerosols. The ambient electrons and light ions in the mesosphere are prevented from being collected by a magnetic field. The magnetic force causes these lighter particles to turn so that they miss the collecting patch.

Very little is understood about the microphysics of noctilucent clouds. It is not known whether the ice crystals comprising them are of cubic habit, as has been suggested, or whether they are hexagonal, as in tropospheric clouds. It has not been established whether the crystal habit and the crystal growth rates are influenced or controlled by the nuclei present in the upper atmosphere, or whether temperature and humidity conditions play the dominant role in that respect as in the troposphere. It is clear, however, that the size and shape of the individual crystals determine their optical properties and therefore determine how noctilucent clouds interact with transmissions of electromagnetic waves. Our experiments were aimed at revealing the habit of noctilucent cloud particles.