Stratosphere


Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler higher up and warmer farther down. The border of the troposphere and stratosphere, the tropopause, is marked by where this inversion begins, which in terms of atmospheric thermodynamics is the equilibrium level. The stratosphere is situated between about 10 km (6 miles) and 50 km (31 miles) altitude above the surface at moderate latitudes, while at the poles it starts at about 8 km (5 miles) altitude.

The stratosphere is layered in temperature because it is heated from above by absorption of ultraviolet radiation from the Sun. Within this layer, temperature increases as altitude increases (see temperature inversion); the top of the stratosphere has a temperature of about 270 K (−3°C or 26.6°F), just slightly below the freezing point of water. [Seinfeld, J. H., and S. N. Pandis, (2006), Atmospheric Chemistry and Physics: From Air Pollution to Climate Change 2nd ed, Wiley, New Jersey] This top is called the stratopause, above which temperature again decreases with height. The 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. The heating is caused by an ozone layer that absorbs solar ultraviolet radiation, heating the upper layers of the stratosphere. The base of the stratosphere occurs where heating by conduction from above and heating by convection from below (through the troposphere) balance out; hence, the stratosphere begins at lower altitudes near the poles due to the lower ground temperature there.

Commercial airliners typically cruise at an altitude near 10 km in temperate latitudes, in the lower reaches of the stratosphere.Fact|date=September 2008 They do this to stay above any hard weather. This is to avoid atmospheric turbulence from the convection in the troposphere. Turbulence experienced in the cruise phase of flight is often caused by convective overshoot from the troposphere below. Similarly, most gliders soar on thermal plumes that rise through the troposphere above warm patches of ground; these plumes end at the base of the stratosphere, setting a limit to how high gliders can fly in most parts of the world. (Some gliders do fly higher, using ridge lift from mountain ranges to lift them into the stratosphere.)

The stratosphere is a region of intense interactions among radiative, dynamical, and chemical processes, in which horizontal mixing of gaseous components proceeds much more rapidly than vertical mixing. 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 ozone or water vapor.

In northern hemispheric winter, sudden stratospheric warmings can often be observed which are caused by the absorption of Rossby waves in the stratosphere.

See also

* Léon Teisserenc de Bort (the discoverer of the stratosphere)
* Paris Gun (first artificial object to reach stratosphere)
* SR-71 Blackbird
* Concorde
* Lockheed U-2
* RQ-4 Global Hawk
* Twinjets service ceiling
* Le Grand Saut

References

External links


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Look at other dictionaries:

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  • stratosphère — [ stratɔsfɛr ] n. f. • 1898; de strato et sphère ♦ Couche de l atmosphère située de 18 à 50 km d altitude (⇒ stratopause), entre la troposphère et la mésosphère. ● stratosphère nom féminin Zone de l atmosphère d une planète située au dessus de la …   Encyclopédie Universelle

  • stratosphere — (n.) 1909, from Fr. stratosphère, lit. sphere of layers, coined by French meteorologist Léon Philippe Teisserenc de Bort (1855 1913) from L. stratus a spreading out (from pp. stem of sternere to spread out; see STRUCTURE (Cf. structure)) + Fr.… …   Etymology dictionary

  • stratosphere — [strat′ə sfir΄] n. [Fr stratosphère < ModL stratum, STRATUM + Fr sphère,SPHERE] 1. the atmospheric zone or shell located above the tropopause at an altitude of c. 20 to 50 km ( c. 12 to 31 mi) and characterized by an increase in temperature… …   English World dictionary

  • stratosphere — ► NOUN 1) the layer of the earth s atmosphere above the troposphere and below the mesosphere. 2) informal the very highest levels of something. DERIVATIVES stratospheric adjective …   English terms dictionary

  • Stratosphère — Pour les articles homonymes, voir Stratosphère (homonymie). Schéma des couches de l atmosphère (à l echelle). La stratosphère ( 50 km) ne compte que pour environ 1% de l atmosphère. On considère que l exosphère (observable depuis …   Wikipédia en Français

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  • stratosphere — stratospheric /strat euh sfer ik, sfear /, stratospherical, adj. /strat euh sfear /, n. 1. the region of the upper atmosphere extending upward from the tropopause to about 30 miles (50 km) above the earth, characterized by little vertical change… …   Universalium

  • stratosphere — strat|os|phere [ˈstrætəsfıə US sfır] n [Date: 1900 2000; : French; Origin: stratosphère, from Modern Latin stratum ( STRATUM) + French sphère sphere ] 1.) the stratosphere the outer part of the air surrounding the Earth, from ten to fifty… …   Dictionary of contemporary English

  • stratosphere — [[t]stræ̱təsfɪə(r)[/t]] 1) N SING: the N The stratosphere is the layer of the earth s atmosphere which lies between 10 and 50 kilometres above the earth. 2) N SING: the N If you say that someone or something climbs or is sent into the… …   English dictionary


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