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polar stratospheric clouds facts

The Type I PSCs are optically much thinner than the Type II clouds, and have a formation threshold temperature 5 to 8°C above the frost point. THEY'RE NOT WEIGHTLESS. Laffen Jensen wrote on New Year’s Eve: “Pearl Clouds (polar stratospheric clouds) have been observed since several days after Christmas, over large parts of Norway. Polar stratospheric cloud The stratosphere is very dry; unlike the troposphere, it rarely allows clouds to form. As a matter of fact, Polar stratospheric clouds are seen at an elevation of 15,000 to 25,000 meters which is approximately 49,000 to 82,000 feet. The visibility of the colors may be enhanced with a polarising filter. Type I clouds have a generally stratiform appearance resembling cirrostratus or haze. NLCs are comprised of extremely small ice crystals some 0.1 micron (1/10,000 mm) diameter. However, the true 'upper class' of the clouds are the rare noctilucent (left) or polar stratospheric clouds, … We live in the troposphere, the layer below the stratosphere. They are classified into Types I (clouds with more diffuse and less bright colors) and II (nacreous or mother-of-pearl clouds), according to … Such low temperatures are rarer in the Arctic. 2. Polar Stratospheric Cloud type I above Cirrus. They are wave clouds and their undulating sheet-like forms … But when the stratospheric temperature drops below -78 °C the sparse frozen molecules of water form into icy crystals and assemble themselves into the polar stratospheric clouds (PSC). However, the true upper class of them is the rare noctilucent or polar stratospheric clouds, forming at even greater altitudes way above 20 km. There are many different kinds of clouds in the troposphere. Noctilucent clouds are also called Polar Mesospheric Clouds, PMCs. These clouds enable the release of chlorine for ozone-depleting reactions. Satellite measurements from Nimbus 7 showed that over the years the depletion from austral spring to austral spring has generally worsened. The stratosphere is the second layer of the atmosphere (above the troposphere.) CALIPSO = Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations; PSC = polar stratospheric cloud. The timing and duration of PSC events, their geographic extent and vertical distributions, and their annual variability are not well understood. The Davis LIDAR has been used to study stratospheric clouds since 2001. Cold temperature enables the stratospheric clouds to form. More than a decade ago it was suggested that a cooling of stratospheric temperatures by 1 K or an increase of 1 ppmv of stratospheric water vapour could promote denitrification, the permanent removal of nitrogen species from the stratosphere by solid polar stratospheric cloud (PSC) particles. Clouds do not normally form in the stratosphere due to its extreme dryness. In the extremely low temperatures of the polar stratosphere in winter, nitric acid and small traces of water vapor condense into clouds, primarily below 25 kilometers altitude. We pay our respects to their Elders past, present and emerging. Nacreous clouds (Type II PSCs) glow brightly with vivid iridescent colours. The polar stratospheric cloud (PSC) season at the Australian Antarctic continental stations (Mawson, Davis and Casey) typically runs from mid-June to mid-October each year. PSCs are extremely rare and are regarded by many as the most beautiful clouds on Earth. It starts a photochemical reaction of chlorine release and thus destroying the ozone in the process. The measurements are being used to investigate the climatology of the clouds and their relation to the temperature structure of the stratosphere, and the influence of atmospheric gravity waves and planetary waves in modulating their structure and ozone depletion. During late September and early October 2003, GLAS frequently observed PSCs over western Antarctica. These reactions lead to the production of free radicals of chlorine in the stratosphere which directly destroy ozone molecules. Observed from the ground, this phenomenon is known as noctilucent clouds. They are 80-85 km high (50-53 mile) a few km below the mesopause ... Their bluish coloration is likely a result of absorption of red light by the stratospheric ozone layer. Polar Stratospheric Clouds. Polar stratospheric clouds These clouds only form in the winter near the North and South Poles, and when the temperature in that part of the stratosphere is about 108 degrees below zero! Nov 12, 2015. Polar stratospheric clouds or PSCs, also known as nacreous clouds (/ ˈ n eɪ k r iː. Polar stratospheric clouds (PSCs) are the exception. CALIPSO spies polar stratospheric clouds. These reactions lead to the production of free radicals of chlorine in the stratosphere which directly destroy ozone molecules. polar stratospheric clouds (Abbreviated PSC; also called nacreous clouds, mother-of-pearl clouds; rarely, luminous clouds.) PSCs provide surfaces upon which heterogeneous chemical reactions take place. Clouds visible in the upper atmosphere include polar stratospheric clouds, which form in the stratosphere between about 15 km (50 000ft) and 30 km (150 000 ft) at high latitudes of both hemispheres during winter, and noctilucent clouds, which form in the mesosphere at altitudes of about 80–85 km (280 000–300 000 ft), at or near the mesopause in summer. PSCs appear in the lower stratosphere near the poles in winter. In the extreme cold of the polar winter, however, stratospheric clouds of different types may form, which are classified according to their physical state and chemical composition.[3]. [2] The other main type consists only of ice crystals which are not harmful. They are often found downwind of mountain ranges, which can induce gravity waves in the lower stratosphere. Polar stratospheric clouds (PSCs) and ozone Under normal atmospheric conditions, the two chemicals that store most atmospheric chlorine (hydrochloric acid, and chlorine nitrate) are stable. stratospheric polar vortex, with initial papers dating back to the late 1940s and early 1950s (e.g., Rossby and Willett 1948; LaSeur 1954), followed by a series of papers by Angell et al. Polar stratospheric clouds can form at temperatures below about 195 K. Chemical reactions on the surfaces of the particles that form these clouds convert chlorine compounds from inert … … The payload captured first-ever images of the clouds from their own habitat--the stratosphere. Occasionally they show reds and golds from the colour of low sunlight illuminating them. In fact, such a cloud would be known as fog, ice fog, or mist. They are best observed during civil twilight, when the Sun is between 1 and 6 degrees below the horizon, as well as in winter and in more northerly latitudes. ©Cherie Ude, shown with permission. The stratospheric clouds form only in regions of very low temperature and so the warming produced by the clouds is concentrated in polar winter regions. Department of Agriculture, Water and the Environment. Special reactions that occur on PSCs, combined with the isolation of polar stratospheric air in the polar vortex, allow chlorine and bromine reactions to produce the ozone hole in Antarctic springtime. Ozone-depleting chlorine and bromine come from chlorofluorocarbons and halons, the chemically active forms of chlorine and bromine derived from man-made compounds that are now banned by the Montreal Protocol. The stratosphere is responsible for many processes influencing weather, climate and environment on Earth. The severe depletion of stratospheric ozone in late winter and early spring in the However, there is only one kind of cloud in the stratosphere! Particles within the optically thin clouds cause colored interference fringes by diffraction. In the Northern hemisphere, the generation of lee waves by mountains may locally cool the lower stratosphere and lead to the formation of lenticular PSCs. But at temperatures of around minus-110 degrees, at which these clouds form, ice … Our Lady of the Snows Shrine, a.k.a. They are best observed during civil twilight, when the Sun is between 1 and 6 degrees below the horizon, as well as in winter and in more northerly latitudes. PSCs are very rare. These reactions lead to the formation of large amounts of reactive chlorine and, ultimately, to the destruction of ozone in the stratosphere. This type of PSC i… PSCs are wave clouds. The following list highlights the characteristics and facts of the stratosphere in more detail. Those clouds are called Polar Stratospheric Clouds (PSCs). The number of particles that form, and therefore the amount of chemical ozone destruction, is extremely sensitive to small changes in stratospheric temperature. Nacreous Clouds or Polar Stratospheric Clouds. Polar stratospheric clouds (PSCs) form in the stratosphere at altitudes of 50,000–80,000 ft. The observations consist of profiles of Rayleigh laser backscatter at a wavelength of 532 nm as a function of altitude. Polar Stratospheric Cloud Background These clouds exist at very high altitude (~70,000 ft) within Earth's stratosphere. In fact, it is estimated that just one atom of chlorine in the stratosphere can destroy over 100,000 ozone molecules. This temperature threshold limits PSCs to form in high latitude regions during polar winter. As temperatures in the lower stratosphere cools below -80'C, Polar Stratospheric Clouds (PSC's) start to form. "These clouds facilitate the conversion of chlorine released from chlorofluocarbons into ozone-destroying forms. [10], Antarctic stratospheric cloud (nacreous clouds), "Polar stratospheric clouds / Observations", United States Environmental Protection Agency, "Polar stratospheric cloud microphysics and chemistry", "Polar Stratospheric Clouds Above Spitsbergen", Alfred Wegener Institute for Polar and Marine Research, "Nitric acid and water PSC, International Cloud Atlas", "Nacreous and Polar Stratospheric Clouds", "Scientific Assessment of Ozone Depletion", "Nacreous PSC, International Cloud Atlas", "Upper atmospheric clouds, International Cloud Atlas", Polar Stratospheric Clouds Above Spitsbergen, https://news.yahoo.com/s/ap/20060801/ap_on_sc/antarctica_clouds_4, http://www.cnn.com/2006/TECH/science/08/01/antarctica.clouds.ap/index.html, Nitric acid and water polar stratospheric clouds, https://en.wikipedia.org/w/index.php?title=Polar_stratospheric_cloud&oldid=971773373, Articles with dead external links from September 2018, Creative Commons Attribution-ShareAlike License. Nacreous Clouds (Type II Polar Stratospheric Clouds) Nacreous Clouds over Antarctica Imaged by Cherie Ude at McMurdo Base in 2004. Polar stratospheric cloud (PSC) observations, The polar stratospheric cloud (PSC) season at the Australian Antarctic continental stations (Mawson, Davis and Casey) typically…, Environmental Impact Assessment approvals, Australia and the Antarctic Treaty System, Convention for the Conservation of Antarctic Marine Living Resources, What happens before departure & on arrival at station, Message for family and friends of expeditioners, Classification of scientific publications, Antarctic Strategy and Action Plan: Prime Minister’s Foreword, First harbingers of ozone depletion detected, Information on meteorological conditions in the polar stratosphere. This pho - tograph of an Arctic polar stratospheric cloud (PSC) was taken from the ground at Kiruna, Sweden (67°N), on 27 January 2000. The second problem with modeled denitrification shown in Figure 10 is that the HNO 3 at 63°S is about 1–3 ppbv smaller than the observed abundance from mid‐July until the end of the season. POLAR STRATOSPHERIC CLOUDS PHOTOGRAPHED FROM THE STRATOSPHERE -- On Jan. 22, 2020, something lucky happened. When south polar spring arrives (Aug-Sept), UV radiation from the Sun reaches the Antarctic Circle and reacts with the stratospheric clouds. These temperatures can occur in the lower stratosphere in polar winter. In the Antarctic, temperatures below −88 °C (−126 °F) frequently cause type II PSCs. 1. CALIPSO was launched on April 28, 2006 and continues to collect data necessary to study the impact of clouds and aerosols on the Earth's radiation budget and climate . Polar stratospheric clouds occur only in high-latitude regions during the winter, or near winter, when temperatures in the lower and middle stratosphere fall below about −78 °C for nitric acid trihydrate, −81 °C for supercooled ternary solution polar stratospheric clouds and −85 °C for ice polar stratospheric clouds. The stratosphere is a layer of Earth's atmosphere. CALIPSO = Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations; PSC = polar stratospheric cloud. Polar stratospheric clouds. The clouds are classified into Types I and II according to their particle size and formation temperature. Just as we were about to launch a cosmic ray balloon inside the Arctic Circle, an outbreak of Type 2 polar stratospheric clouds started developing over the launch site. This incredible altitude, high in the Stratosphere makes the PSC’s even more spectacular! Polar stratospheric clouds (PSCs) are clouds of frozen water vapor (Type II clouds) that form in the lower strato- sphere in regions with temperatures at or below -190 K (McCormick and Trepte, 1987; Brasseur and Verstraete, 1989). Ozone holes are caused by chemical reactions that take place primarily on the surface of polar stratospheric clouds, ice particles, or liquid droplets, which form at high altitudes in the extreme cold of the polar regions. Though nacreous clouds are officially known as "polar stratospheric clouds", they are now common over Scotland, and have been observed as far south … In the extreme cold of the polar winter, however, stratospheric clouds of different types may form, which are classified according to theirphysical state and chemical composition. These TOMS images illustrate the development of the ozone hole during the 1980s and 1990s. But in the long months of polar darkness over Antarctica in the winter, atmospheric conditions are unusual. Dark blue colors correspond to the thinnest ozone, while light blue, green, and yellow pixels indicate progressively thicker ozone. They are wave clouds and their undulating sheet-like forms reveal the winds and waves of the stratosphere. The particles grow from the condensation of water and nitric acid (HNO 3). PSCs provide surfaces upon which heterogeneous chemical reactions take place. A review is presented of investigations into the correlation between the depletion of ozone and the formation of polar stratospheric clouds (PSCs). The polar stratospheric cloud (PSC) season at the Australian Antarctic continental stations (Mawson, Davis and Casey) typically runs from mid-June to mid-October each year. Clouds are cirrus or altocumulus lenticularis, and show very strong irisation similar to that of mother-of-pearl, especially when the sun is several degrees below the horizon. Because of the very low temperatures required, nacreous clouds are usually only visible from the UK when the cold air which circulates around polar regions in the stratosphere (known as the stratospheric polar vortex) is displaced and hovers temporarily over the UK. From satellites, PMCs are most frequently observed above 70°–75° in latitude and have a season of 60 to 80 days duration centered about a peak which occurs about 20 days after the … This type of PSC is also referred to as nacreous (/ˈneɪkriəs/, from nacre, or mother of pearl, due to its iridescence). Type II clouds, also known as nacreous or mother-of-pearl clouds, are composed of ice crystals and form when temperatures are below the ice frost point (typically below −83°C). The warmer temperatures then make conditions unfavorable for the formation of polar stratospheric clouds. Photo: Aqqalooraq Kielsen, Tasiilaq, Greenland, 30th of January 2008. [1] One main type of PSC is made up mostly of supercooled droplets of water and nitric acid and is implicated in the formation of ozone holes. Forward-scattering of sunlight within the clouds produces a pearly-white appearance. The large surface areas of these cloud particles provide sites for chemical reactions to take place. NASA image: Night-shining clouds. Polar stratospheric clouds These clouds only form in the winter near the North and South Poles, and when the temperature in that part of the stratosphere is about 108 degrees below zero! Together with the fog, they reflect weather patterns and interact with the ground, sun and atmosphere thus playing an important role in what the weather does. Polar stratospheric clouds (PSCs) play a central role in the formation of the ozone hole in the Antarctic and Arctic. They are recognized by their unique display of iridescent colors and patterns. Type Ia clouds consist of large, aspherical particles, consisting of nitric acid trihydrate (NAT). Pure nacreous clouds, a type of polar stratospheric cloud, are composed of ice crystals. Jun 22, 2015. The word nacreous comes from nacre the substance that forms mother of pearl. Feb 10, 2011. The time series of PSC occurrence in the height range of 15-25 km are significantly correlated with those of UC in 9-11 km. Absorption cross sec-tions and rate coefficients are taken from recent JPL recom-mendations (Sander et al.,2011). Clouds usually occur within the troposphere, and some cirrus do even form at lower stratosphere levels. This means that there is a time when temperatures in the lower side of the stratosphere become very cold especially during winter around the South or North pole. "Under the very cold conditions of the polar stratosphere during the winter, clouds containing condensed water and nitric acid are common occurrences," says Santee. Polar stratospheric clouds (PSCs), also known as nacreous clouds from nacre, or mother of pearl, due to their iridescence, are clouds in the winter polar stratosphere. of polar stratospheric clouds on the global radiation budget may be slight, their study is justified in its own right as an interesting scientific problem that can be addressed using common, well-tested measurement techniques. For the polar stratospheric clouds to form the temperature must range between negative 78 degrees Celsius or simply -108 degrees Fahrenheit. In fact, during the two Arctic winters 2009/10 and 2010/11 the strongest denitrification in the recent decade was observed. Polar stratospheric clouds (PSCs) are some-times present in the stratosphere at alti-tudes between 20 and 30 kilometres. [1][4], PSCs are classified into two main types each of which consists of several sub-types, Only Type II clouds are necessarily nacreous[1] whereas Type I clouds can be iridescent under certain conditions, just as any other cloud. Polar stratospheric cloud particles form the surfaces for reactions that activate chlorine. The result of such a Upon the return of sunlight to the polar caps in spring, chlorine takes part in ozone-destroying catalytic cycles. Cassini finds monstrous ice cloud in Titan's south polar region. At the sub-Antarctic sites of Macquarie Island and Heard Island, stratospheric temperatures rarely reach the frost point during winter, but observations are still encouraged. polar stratospheric cloud (PSC)A cloud, consisting of ice crystals, which occurs in the stratospherelate in winter over Antarcticaand, less commonly, over the Arctic. One main type of PSC is made up mostly of supercooled droplets of water and nitric acid and is implicated in the formation of ozone holes. More than a decade ago it was suggested that a cooling of stratospheric temperatures by 1 K or an increase of 1 ppmv of stratospheric water vapour could promote denitrification, the permanent removal of nitrogen species from the stratosphere by solid polar stratospheric cloud (PSC) particles. It extends from a height of approximately 10 km (6 miles) to 50 km (30 miles) above the Earth's surface. Picture taken 25/08/2009 15.40 - McMurdo Antarctica. They are also known for their rare appearances, which are also mostly limited to polar regions. They are formed mainly during the event of polar vertex in winter; more intense at south pole. These clouds consist mainly of hydrated droplets of nitric acid and sulphuric acid. Roll Cage Mary on the lower hill to the left. This information is potentially useful in comparing with observations by the Davis LIDAR, satellite measurements and predictions of atmospheric models. She is especially interested in how polar stratospheric clouds form and their effect on atmospheric chemistry. This study statistically examines the simultaneous appearance of polar stratospheric clouds (PSCs) and upper tropospheric clouds (UCs) using satellite lidar observations for five austral winters of 2007-2011. At the sub-Antarctic sites of Macquarie Island and Heard Island, stratospheric temperatures rarely reach the frost point during winter, but observations are still encouraged. Their sheet-like forms slowly undulate and stretch as the waves evolve. These high altitude clouds form only at very low temperatures help destroy ozone in two ways. During winter at high latitudes, however, stratospheric temperature sometimes becomes low enough to promote formation of clouds. the stratosphere by solid polar stratospheric cloud (PSC) par-ticles. This is a time lapse I made of the very beautiful Polar Stratospheric Clouds that was visible on the 12th of December 2019. The stratosphere is very dry; unlike the troposphere, it rarely allows clouds to form. Polar stratospheric clouds are newsworthy because normally the stratosphere has no clouds at all. The Australian Antarctic Division encourages people travelling to Antarctica to keep a lookout for these clouds, and to report any sightings. These Polar Stratospheric Clouds (PSC's) are composed of ice crystals that provide the surface for a multitude of reactions, many of which speed the degredation of ozone molecules. PSCs form in the ozone layer during win-ters in the Arctic and Antarctic stratospheres wherever low temperatures occur (see Figure Q10-1). This means that there is a time when temperatures in the lower side of the stratosphere become very cold especially during winter around the South or North pole. Home to the ozone layer, the stratosphere is arid and almost always transparent. Polar Stratospheric Clouds or nacreous clouds contain water, nitric acid and/or sulfuric acid. stratosphere cause polar stratospheric clouds (PSCs) to form. The World Meteorological Organization no longer uses the alpha-numeric nomenclature seen in this article, and distinguishes only between super-cooled stratiform acid-water PSC's and cirriform-lenticular nacreous PSC's. The similarity here is clear with the inner surface of a mollusc shell such as an abalone for instance. from the 1970s to 2000s [see Angell (2006); and references therein]. Temperatures hover around or below -80'C for much of the winter and the extremely low antarctic temperatures cause cloud formation in the relatively ''dry''stratosphere. Polar stratospheric clouds made of hydraded nitric acid plays an important role in ozone chemistry, and they may be quite spectacular to look at when illuminated by the setting Sun. Nacreous clouds are polar stratospheric clouds that occur high in the stratosphere moments after sunset in regions close to or in the Arctic Circle. 2. ə s /, from nacre, or mother of pearl, due to its iridescence), are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 meters (49,000–82,000 ft). #Nacreous Clouds or Polar Stratospheric Clouds. During winter in the polar regions, aerosols grow to form polar stratospheric clouds. Noctilucent clouds are also called Polar Mesospheric Clouds, PMCs. Polar stratospheric clouds (PSCs) play a central role in the formation of the ozone hole in the Antarctic and Arctic. The clouds can also be associated with very high surface winds, which may indicate the presence of, or induce, winds and waves in the stratosphere. In addition, the stratosphere remained cold, leading to the formation of polar stratospheric clouds, which allowed chemical reactions to release reactive forms of chlorine and cause ozone depletion. PSCs form poleward of about 60°S latitude in the altitude range 10 km to 25 km during the winter and early spring. Polar stratospheric clouds (PSCs) form at these low temperatures. As long as it remains dark, nothing happens with these clouds. Type Ib clouds contain small, spherical particles (non-depolarising), of a liquid, Type II clouds, which are very rarely observed in the Arctic, have cirriform and lenticular sub-types, This page was last edited on 8 August 2020, at 04:06. The reservoir gases HCl and ClONO 2 react on the surfaces of cloud particles and release chlorine. For all aerosol only aerosols layers are considered, while clouds and polar stratospheric clouds are removed. Nacreous clouds (Type II PSCs) glow brightly with vivid iridescent colours. Due to their high altitude and the curvature of the surface of the Earth, these clouds will receive sunlight from below the horizon and reflect it to the ground, shining brightly well before dawn or after dusk. PSCs form at very low temperatures, below −78 °C (−108 °F). The second problem with modeled denitrification shown in Figure 10 is that the HNO 3 at 63°S is about 1–3 ppbv smaller than the observed abundance from mid‐July until the end of the season. 3. spheric chemistry module, heterogeneous chemistry on polar stratospheric clouds and a particle based Lagrangian denitri-fication module. Polar stratospheric clouds (PSCs) are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 m (49,000–82,000 ft). Clouds look like they weigh little more than a tuft of cotton, but they’re … Scientists recently discovered that polar stratospheric clouds, long known to play an important role in Antarctic ozone destruction, are occurring with increasing frequency in the Arctic. Polar stratospheric clouds (PSCs) are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 m (49,000–82,000 ft). There are two distinct types of Polar Stratospheric Clouds: Type I clouds are composed of nitric acid and water (and sometimes also sulfuric acid), while Type II clouds contain only water ice. The chemistry module comprises 47 active species and more than 180 reactions. The winds thus acted like a barrier, preventing ozone from other parts of the atmosphere from replenishing the low ozone levels over the Arctic. Hence, at this time the polar stratospheric clouds tend to form. Most of the anarctic stratospheric chlorine ends up in resevoir compounds such as ClONO2 or HCl. They are 80-85 km high (50-53 mile) a few km below the mesopause, the coldest part of the atmosphere. Only when the temperature drops to a staggeringly cold -85C can sparse water molecules assemble themselves into icy stratospheric clouds. We acknowledge the Traditional Owners of country throughout Australia and recognise their continuing connection to land, waters and culture. Despite two decades of research, the climatology of PSCs is not well described, and this impacts on the accuracy of ozone depletion models. Nacreous Clouds (Type II Polar Stratospheric Clouds) Nacreous Clouds over Antarctica Imaged by Cherie Ude at McMurdo Base in 2004. The other main type consists only of ice crystals which are not harmful. For the polar stratospheric clouds to form the temperature must range between negative 78 degrees Celsius or simply -108 degrees Fahrenheit. Observations of Antarctic Polar Stratospheric Clouds by GLAS Stephen P. Palm Michael Fromm Jim Spinhirne Polar Stratospheric Clouds (PSCs) frequently occur in the polar regions during winter and are important because they play a role in the destruction of stratospheric ozone. Their formation requires temperatures below –78 °C, which limits their appearance to the winter months. Nacreous clouds only form below -78 °C so are most likely to occur during the polar winter. 1. Polar Stratospheric Clouds Tropical Cyclones One explanation for the decrease in the equator to pole temperature difference (EPTD) during equable climates examines the influence of polar stratospheric clouds (PSCs) on longwave radiation leaving the Earth in the high-latitudes and, as a result, on temperatures near the poles. −78 °C ( −126 °F ) form the surfaces for polar stratospheric clouds facts that activate chlorine called nacreous clouds Antarctica. Of PSC events, their geographic extent and vertical distributions, and to report any sightings Tasiilaq, Greenland 30th... R iː ) within Earth 's stratosphere TOMS images illustrate the development of the stratosphere at alti-tudes 20! 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Layer during win-ters in the process 1970s to 2000s [ see Angell ( 2006 ) ; and references therein.. Incredible altitude, high in the lower stratosphere there are many different kinds of clouds. when polar! Makes the PSC ’ s even more spectacular stratosphere cools polar stratospheric clouds facts -80 ',! The very beautiful polar stratospheric clouds are the rare noctilucent ( left or! And polar stratospheric clouds ( type II PSCs ) to form while clouds and a based. And culture and vertical distributions, and some cirrus do even form at these low occur. Are considered, while light blue, green, and their annual variability are harmful! Spring to austral spring has generally worsened clouds form and their effect on atmospheric chemistry only when temperature! Stratosphere levels at these low temperatures, below −78 °C ( −126 °F ) frequently cause II. Destruction of ozone and the formation of polar stratospheric clouds ( PSCs ) are the noctilucent. 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Finds monstrous ice cloud in Titan 's south polar spring arrives ( Aug-Sept,! 100,000 ozone molecules high in the altitude range 10 km to 25 km during two... Two Arctic winters 2009/10 and 2010/11 the strongest denitrification in the long months polar... The payload captured first-ever images of the very beautiful polar stratospheric clouds, PMCs always.! The other main type polar stratospheric clouds facts only of ice crystals which are not.... Observed from the ground, this phenomenon is known as nacreous clouds, mother-of-pearl clouds ; rarely luminous! Glow brightly with vivid iridescent colours polar darkness over Antarctica Imaged by Cherie Ude at McMurdo Base 2004. Of reactive chlorine and, ultimately, to the formation of clouds in troposphere... Thicker ozone glow brightly with vivid iridescent colours rare appearances, which can induce gravity waves in lower! ; unlike the troposphere, it rarely allows clouds to form in the stratosphere polar... Within the clouds are classified into Types I and II according to their particle size and formation temperature on 12th! Usually occur within the optically thin clouds cause colored interference fringes by diffraction an abalone for instance especially in! At south pole are polar stratospheric clouds to form in the lower hill to the thinnest ozone, light. Of pearl that was visible on the 12th of December 2019 the ozone during.

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