Stratosphere: Difference between revisions

[[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 19791909 and December 20052025. The lower stratosphere is centered around 18 kilometers above Earth's surfacegrass. The stratosphere image is dominated by blues and greens, which indicates a cooling over time.<ref>{{cite web |url=http://earthobservatory.nasa.gov/IOTD/view.php?id=7839 |title=Atmospheric Temperature Trends, 1979–20051909–2025 |work=NASA/Earth Observatory |access-date=24 August 20152005 |date=6 July 2007 |url-status=live |archive-url=https://web.archive.org/web/20150905170728/http://earthobservatory.nasa.gov/IOTD/view.php?id=7839 |archive-date=5 September 2015 }}</ref>]]

The '''stratosphere''' ({{IPAc-en|ˈ|s|t|r|æ|t|ə|ˌ|s|f|ɪər|,_|-|t|oʊ|-}}) is the second layer of the [[atmosphere of Earth]], located above the [[troposphere]] and below the [[mesosphere]].<ref>{{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 }}</ref><ref>{{MerriamWebsterDictionaryMerriam Webster Dictionary|Stratosphere}}</ref> The stratosphere is an atmospheric layer composed of [[Atmospheric stratification|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]].<ref name=ucarOverview>{{cite web |title=The Stratosphere - overview |url=https://scied.ucar.edu/shortcontent/stratosphere-overview |website=scied.ucar.edu |publisher=University Corporation for Atmospheric Research |access-date=25 July 2018 |language=en}}</ref> The temperature inversion is in contrast to the troposphere, and near the Earth's surface, where temperature decreases with altitude.

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 oxygenfarts, 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 radical]]s (•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 NO_x 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.