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{{Other uses}}{{short description|Layer of the atmosphere above the troposphere}}File:ISS-46 Soyuz TMA-17M reentry.jpg|thumb|upright=1.25|Afterglow of the troposphere (orange), the stratosphere (blue) and the mesosphere (dark) at which atmospheric entry begins, leaving contrails, such as in this case of a spacecraftspacecraft(File:Stratosphere Temperature Trend.jpg|thumb|This image shows the temperature trend in the lower stratosphere as measured by a series of satellite-based instruments between January 1979 and December 2005. The lower stratosphere is centered around 18 kilometers above Earth’s surface. The stratosphere image is dominated by blues and greens, which indicates a cooling over time.WEB,earthobservatory.nasa.gov/IOTD/view.php?id=7839, Atmospheric Temperature Trends, 1979–2005, NASA/Earth Observatory, 24 August 2015, 6 July 2007, live,earthobservatory.nasa.gov/IOTD/view.php?id=7839," title="web.archive.org/web/20150905170728earthobservatory.nasa.gov/IOTD/view.php?id=7839,">web.archive.org/web/20150905170728earthobservatory.nasa.gov/IOTD/view.php?id=7839, 5 September 2015, )File:Atmosphere layers-en.svg|thumb|upright=0.8|Diagram showing the five primary layers of the Earth’s atmosphere: exosphere, thermosphere, mesosphere, stratosphere, and tropospheretroposphereThe stratosphere ({{IPAc-en|ˈ|s|t|r|æ|t|É™|ËŒ|s|f|ɪər|,_|-|t|oÊŠ|-}}) is the second layer of the atmosphere of Earth, located above the troposphere and below the mesosphere.{{Citation |last=Jones |first=Daniel |author-link=Daniel Jones (phonetician) |title=English Pronouncing Dictionary |editor=Peter Roach |editor2=James Hartmann |editor3=Jane Setter |place=Cambridge |publisher=Cambridge University Press |orig-year=1917 |year=2003 |isbn=978-3-12-539683-8 }}{{MerriamWebsterDictionary|Stratosphere}} The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air high in the sky and the cool layers of air in the low sky, close to the planetary surface of the Earth. The increase of temperature with altitude is a result of the absorption of the Sun’s ultraviolet (UV) radiation by the ozone layer.WEB, The Stratosphere - overview,scied.ucar.edu/shortcontent/stratosphere-overview, scied.ucar.edu, University Corporation for Atmospheric Research, 25 July 2018, en, The temperature inversion is in contrast to the troposphere, and near the Earth’s surface, where temperature decreases with altitude.Between the troposphere and stratosphere is the tropopause border that demarcates the beginning of the temperature inversion. Near the equator, the lower edge of the stratosphere is as high as {{convert|20|km|sigfig=2|ft mi|abbr=on}}, at midlatitudes around {{convert|10|km|sigfig=2|ft mi|abbr=on}}, and at the poles about {{convert|7|km|sigfig=2|ft mi|abbr=on}}. Temperatures range from an average of {{convert|-51|C|sigfig=2|F K|abbr=on}} near the tropopause to an average of {{convert|-15|C|sigfig=2|F K|abbr=on}} near the mesosphere.WEB, NWS JetStream - Layers of the Atmosphere,www.weather.gov/jetstream/layers, www.weather.gov, EN-US, Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter).WEB, Nasa Ozone Watch: Polar vortex facts,ozonewatch.gsfc.nasa.gov/facts/vortex_NH.html, ozonewatch.gsfc.nasa.gov, en-us, Winds in the stratosphere can far exceed those in the troposphere, reaching near {{convert|60|m/s|km/h mph|abbr=on}} in the Southern polar vortex.

Discovery

In 1902, Léon Teisserenc de Bort from France and Richard Assmann from Germany, in separate but coordinated publications and following years of observations, published the discovery of an isothermal layer at around 11–14 km (6.8-8.7 mi), which is the base of the lower stratosphere. This was based on temperature profiles from mostly unmanned and a few manned instrumented balloons.{{Citation |last=Steinhagen |first=Hans |title=Der Wettermann - Leben und Werk Richard Aßmanns |place=Neuenhagen, Germany |publisher=Findling |year=2005 |isbn=978-3-933603-33-3 }}

Ozone layer

{{Further|Ozone layer}}(File:Layersofozone 1.jpeg 1240x510 q85 subsampling-2.jpg|thumb|The ozone layer in the stratosphere blocks harmful UV radiation from reaching the surface of the Earth. A gamma ray burst would deplete the ozone layer, allowing UV radiation through.)The mechanism describing the formation of the ozone layer was described by British mathematician and geophysicist Sydney Chapman in 1930, and is known as the Chapman cycle or ozone–oxygen cycle.WEB, CHAPTER 10. STRATOSPHERIC OZONE,acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html, 2020-10-20, acmg.seas.harvard.edu, 2019-09-30,acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html," title="web.archive.org/web/20190930034719acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html,">web.archive.org/web/20190930034719acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html, dead, Molecular oxygen absorbs high energy sunlight in the UV-C region, at wavelengths shorter than about 240 nm. Radicals produced from the homolytically split oxygen molecules combine with molecular oxygen to form ozone. Ozone in turn is photolysed much more rapidly than molecular oxygen as it has a stronger absorption that occurs at longer wavelengths, where the solar emission is more intense. Ozone (O3) photolysis produces O and O2. The oxygen atom product combines with atmospheric molecular oxygen to reform O3, releasing heat. The rapid photolysis and reformation of ozone heat the stratosphere, resulting in a temperature inversion. This increase of temperature with altitude is characteristic of the stratosphere; its resistance to vertical mixing means that it is stratified. Within the stratosphere temperatures increase with altitude (see temperature inversion); the top of the stratosphere has a temperature of about 270 K (−3°C or 26.6°F).Seinfeld, J. H., and S. N.(2006), Atmospheric Chemistry and Physics: From Air Pollution to Climate Change 2nd ed, Wiley, New JerseyThis vertical stratification, with warmer layers above and cooler layers below, makes the stratosphere dynamically stable: there is no regular convection and associated turbulence in this part of the atmosphere. However, exceptionally energetic convection processes, such as volcanic eruption columns and overshooting tops in severe supercell thunderstorms, may carry convection into the stratosphere on a very local and temporary basis. Overall, the attenuation of solar UV at wavelengths that damage DNA by the ozone layer allows life to exist on the surface of the planet outside of the ocean. All air entering the stratosphere must pass through the tropopause, the temperature minimum that divides the troposphere and stratosphere. The rising air is literally freeze dried; the stratosphere is a very dry place. The top of the stratosphere is called the stratopause, above which the temperature decreases with height.

Formation and destruction

{{Further|Ozone–oxygen cycle}}Sydney Chapman gave a correct description of the source of stratospheric ozone and its ability to generate heat within the stratosphere;{{Citation needed|date=October 2021}} he also wrote that ozone may be destroyed by reacting with atomic oxygen, making two molecules of molecular oxygen. We now know that there are additional ozone loss mechanisms and that these mechanisms are catalytic, meaning that a small amount of the catalyst can destroy a great number of ozone molecules. The first is due to the reaction of hydroxyl radicals (•OH) with ozone. •OH is formed by the reaction of electrically excited oxygen atoms produced by ozone photolysis, with water vapor. While the stratosphere is dry, additional water vapor is produced in situ by the photochemical oxidation of methane (CH4). The HO2 radical produced by the reaction of OH with O3 is recycled to OH by reaction with oxygen atoms or ozone. In addition, solar proton events can significantly affect ozone levels via radiolysis with the subsequent formation of OH. Nitrous oxide (N2O) is produced by biological activity at the surface and is oxidised to NO in the stratosphere; the so-called NOx radical cycles also deplete stratospheric ozone. Finally, chlorofluorocarbon molecules are photolysed in the stratosphere releasing chlorine atoms that react with ozone giving ClO and O2. The chlorine atoms are recycled when ClO reacts with O in the upper stratosphere, or when ClO reacts with itself in the chemistry of the Antarctic ozone hole.Paul J. Crutzen, Mario J. Molina and F. Sherwood Rowland were awarded the Nobel Prize in Chemistry in 1995 for their work describing the formation and decomposition of stratospheric ozone.WEB, The Nobel Prize in Chemistry 1995,www.nobelprize.org/prizes/chemistry/1995/summary/, 2020-07-21, NobelPrize.org, en-US,

Aircraft flight

File:Boeing_737_view_1.jpg|alt=A generic Boeing 737-800 cruising at 32,000 feet. Below it is a pack of clouds. Above it is a vivid, ambient blue sky.|left|thumb|262x262px|Aircraft typically cruise at the stratosphere to avoid turbulence rampant in the troposphere. The blue beam in this image is the ozone layer, beaming further to the mesosphere. The ozone heats the stratosphere, making conditions stable. The stratosphere is also the altitude limit of jets and weather balloons, as air is roughly a thousand times thinner there than at the troposphere.WEB, The Stratosphere - overview {{!, UCAR Center for Science Education|url=https://scied.ucar.edu/learning-zone/atmosphere/stratosphere-overview#:~:text=Commercial%20jet%20aircraft%20fly%20in,the%20lower,%20more%20humid%20troposphere.|access-date=2021-02-06|website=|publisher=National Center for Science EducationNational Center for Science EducationCommercial airliners typically cruise at altitudes of {{convert|9|–|12|km|ft|abbr=on}} which is in the lower reaches of the stratosphere in temperate latitudes.WEB,hypertextbook.com/facts/2003/DanielCheng.shtml, Altitude of a commercial jet airplane, Daniel, Cheng, 2003, The Physics Factbook, Elert, Glenn, 2022-01-21, This optimizes fuel efficiency, mostly due to the low temperatures encountered near the tropopause and low air density, reducing parasitic drag on the airframe. Stated another way, it allows the airliner to fly faster while maintaining lift equal to the weight of the plane. (The fuel consumption depends on the drag, which is related to the lift by the lift-to-drag ratio.) It also allows the airplane to stay above the turbulent weather of the troposphere.The Concorde aircraft cruised at Mach 2 at about {{convert|60000|ft|km|0|abbr=on}}, and the SR-71 cruised at Mach 3 at {{convert|85000|ft|km|0|abbr=on}}, all within the stratosphere.Because the temperature in the tropopause and lower stratosphere is largely constant with increasing altitude, very little convection and its resultant turbulence occurs there. Most turbulence at this altitude is caused by variations in the jet stream and other local wind shears, although areas of significant convective activity (thunderstorms) in the troposphere below may produce turbulence as a result of convective overshoot.On October 24, 2014, Alan Eustace became the record holder for reaching the altitude record for a manned balloon at {{convert|135,890|ft|sigfig=5|abbr=on}}.NEWS, Markoff, John, 2014-10-24, Parachutist’s Record Fall: Over 25 Miles in 15 Minutes (Published 2014), en-US, The New York Times,www.nytimes.com/2014/10/25/science/alan-eustace-jumps-from-stratosphere-breaking-felix-baumgartners-world-record.html, 2020-10-20, 0362-4331, Eustace also broke the world records for vertical speed skydiving, reached with a peak velocity of 1,321 km/h (822 mph) and total freefall distance of {{convert|123,414|ft|sigfig=5|abbr=on}} – lasting four minutes and 27 seconds.NEWS,www.bbc.com/news/world-us-canada-29766189, Google’s Alan Eustace beats Baumgartner’s skydiving record, BBC News, live,www.bbc.com/news/world-us-canada-29766189," title="web.archive.org/web/20141025121736www.bbc.com/news/world-us-canada-29766189,">web.archive.org/web/20141025121736www.bbc.com/news/world-us-canada-29766189, 2014-10-25, 2014-10-24,

Circulation and mixing

The stratosphere is a region of intense interactions among radiative, dynamical, and chemical processes, in which the horizontal mixing of gaseous components proceeds much more rapidly than does vertical mixing. The overall circulation of the stratosphere is termed as Brewer-Dobson circulation, which is a single-celled circulation, spanning from the tropics up to the poles, consisting of the tropical upwelling of air from the tropical troposphere and the extra-tropical downwelling of air. Stratospheric circulation is a predominantly wave-driven circulation in that the tropical upwelling is induced by the wave force by the westward propagating Rossby waves, in a phenomenon called Rossby-wave pumping.An interesting feature of stratospheric circulation is the quasi-biennial oscillation (QBO) in the tropical latitudes, which is driven by gravity waves that are convectively generated in the troposphere. The QBO induces a secondary circulation that is important for the global stratospheric transport of tracers, such as ozoneN.Butchart, A.A. Scaife, J. Austin, S.H.E. Hare, J.R. Knight. Quasi-biennial oscillation in ozone in a coupled chemistry-climate model {{webarchive|url=https://web.archive.org/web/20140518230712onlinelibrary.wiley.com/doi/10.1029/2002JD003004/abstract |date=2014-05-18 }}, Journal of Geophysical Research. or water vapor.Another large-scale feature that significantly influences stratospheric circulation is the breaking planetary wavesM.E. McIntyre, T.N. Palmer. Breaking planetary waves in the stratosphere {{webarchive|url=https://web.archive.org/web/20170317055813www.nature.com/nature/journal/v305/n5935/abs/305593a0.html |date=2017-03-17 }}, Nature. resulting in intense quasi-horizontal mixing in the midlatitudes. This breaking is much more pronounced in the winter hemisphere where this region is called the surf zone. This breaking is caused due to a highly non-linear interaction between the vertically propagating planetary waves and the isolated high potential vorticity region known as the polar vortex. The resultant breaking causes large-scale mixing of air and other trace gases throughout the midlatitude surf zone. The timescale of this rapid mixing is much smaller than the much slower timescales of upwelling in the tropics and downwelling in the extratropics.During northern hemispheric winters, sudden stratospheric warmings, caused by the absorption of Rossby waves in the stratosphere, can be observed in approximately half of winters when easterly winds develop in the stratosphere. These events often precede unusual winter weather M.P. Baldwin and T.J. Dunkerton. ‘Stratospheric Harbingers of Anomalous Weather Regimes {{webarchive|url=https://web.archive.org/web/20140112084150www.sciencemag.org/content/294/5542/581.short |date=2014-01-12 }}, Science Magazine. and may even be responsible for the cold European winters of the 1960s.A.A. Scaife, J.R. Knight, G.K. Vallis, C.K. Folland. A stratospheric influence on the winter NAO and North Atlantic surface climate {{webarchive|url=https://web.archive.org/web/20140518230707onlinelibrary.wiley.com/doi/10.1029/2005GL023226/abstract |date=2014-05-18 }}’’, Geophysical Research Letters.Stratospheric warming of the polar vortex results in its weakening.WEB, How Sudden Stratospheric Warming Affects the Whole Atmosphere,eos.org/features/how-sudden-stratospheric-warming-affects-the-whole-atmosphere, 2020-07-21, Eos, 20 March 2018, en-US, When the vortex is strong, it keeps the cold, high-pressure air masses contained in the Arctic; when the vortex weakens, air masses move equatorward, and results in rapid changes of weather in the mid latitudes.

Upper-atmospheric lightning

File:Gigantic jet NOIRLab.jpg|thumb|Lightning extending above the troposphere into the stratosphere as blue jet and reaching into the mesosphere as red sprite ]] Upper-atmospheric lightning is a family of short-lived electrical-breakdown phenomena that occur well above the altitudes of normal lightning and storm clouds. Upper-atmospheric lightning is believed to be electrically induced forms of luminous plasma. Lightning extending above the troposphere into the stratosphere is referred to as blue jet, and that reaching into the mesosphere as red sprite.

Life

Bacteria

Bacterial life survives in the stratosphere, making it a part of the biosphere.JOURNAL, DasSarma, Priya, DasSarma, Shiladitya, Survival of microbes in Earth’s stratosphere, Current Opinion in Microbiology, 43, 2018, 24–30, 1369-5274, 10.1016/j.mib.2017.11.002, 29156444, 19041112, In 2001, dust was collected at a height of 41 kilometres in a high-altitude balloon experiment and was found to contain bacterial material when examined later in the laboratory.BOOK, Michael Mark Woolfson, Michael Woolfson, Time, Space, Stars & Man: The Story of the Big Bang,books.google.com/books?id=JYH0L2tLYpcC, 2013, World Scientific, 978-1-84816-933-3, 388,

Birds

Some bird species have been reported to fly at the upper levels of the troposphere. On November 29, 1973, a Rüppell’s vulture (Gyps rueppelli) was ingested into a jet engine {{convert|37000|ft|sigfig=5|abbr=on|order=flip}} above the Ivory Coast.JOURNAL , Bar-headed geese (Anser indicus) sometimes migrate over Mount Everest, whose summit is {{convert|8,848|m|sigfig=5|abbr=on}}.WEB,audubonmagazine.org/birds/birds0011.html, Audubon: Birds, Audubonmagazine.org, 2011-11-08, live,archive.wikiwix.com/cache/20110914142753/http://audubonmagazine.org/birds/birds0011.html, 2011-09-14, BOOK, Thomas Alerstam, David A. Christie, Astrid Ulfstrand, Bird Migration,books.google.com/books?id=OQjsL97yyhEC&pg=PA276, 1993, Cambridge University Press, 978-0-521-44822-2, 276,

See also

• Le Grand Saut
• Lockheed U-2
• Overshooting top
• Ozone depletion
• Paris Gun (projectile was the first artificial object to reach the upper stratosphere)
• Perlan Project
• Project Excelsior, world record for highest recorded jump 1961-2012
• Red Bull Stratos, world record for highest recorded jump 2012-2014
• RQ-4 Global Hawk
• Service ceiling
• Upper-atmospheric lightning

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References

{{Reflist}}

External links

{{Wiktionary|stratosphere}}

• Current map of global winds and temperatures at the 10 hPa level.

{{Earth’s atmosphere}}{{Authority control}}