stratosphere

1. The region of the atmosphere above the troposphere and below the mesosphere.
2. An extremely high or the highest point or degree on a ranked scale: business expenses in the stratosphere.

[French stratosphère : Latin strātus, a spreading out; see stratus + -sphère, sphere (from Old French espere; see sphere).]

The atmospheric layer that is immediately above the troposphere and contains most of the Earth's ozone. Here temperature increases upward because of absorption of solar ultraviolet light by ozone. Since ozone is created in sunlight from oxygen, a by-product of photosynthesis, the stratosphere exists because of life on Earth. In turn, the ozone layer allows life to thrive by absorbing harmful solar ultraviolet radiation. The mixing ratio of ozone is largest (10 parts per million by volume) near an altitude of 30 km (18 mi) over the Equator. The distribution of ozone is controlled by solar radiation, temperature, wind, reactive trace chemicals, and volcanic aerosols. See also Atmosphere; Troposphere.

The heating that results from absorption of ultraviolet radiation by ozone causes temperatures generally to increase from the bottom of the stratosphere (tropopause) to the top (stratopause) near 50 km (30 mi), reaching 280 K (45°F) over the summer pole. This temperature inversion limits vertical mixing, so that air typically spends months to years in the stratosphere. See also Tropopause.

The lower stratosphere contains a layer of small liquid droplets. Typically less than 1 micrometer in diameter, they are made primarily of sulfuric acid and water. Occasional large volcanic eruptions maintain this aerosol layer by injecting sulfur dioxide into the stratosphere, which is converted to sulfuric acid and incorporated into droplets. Enhanced aerosol amounts from an eruption can last several years. By reflecting sunlight, the aerosol layer can alter the climate at the Earth's surface. By absorbing upwelling infrared radiation from the Earth's surface, the aerosol layer can warm the stratosphere. The aerosols also provide surfaces for a special set of chemical reactions that affect the ozone layer. Liquid droplets and frozen particles generally convert chlorine-bearing compounds to forms that can destroy ozone. They also tend to take up nitric acid and water and to fall slowly, thereby removing nitrogen and water from the stratosphere. The eruption of Mount Pinatubo (Philippines) in June 1991 is believed to have disturbed the Earth system for several years, raising stratospheric temperatures by more than 1 K (1.8°F) and reducing global surface temperatures by about 0.5 K (0.9°F). See also Aerosol.

Ozone production is balanced by losses due to reactions with chemicals in the nitrogen, chlorine, hydrogen, and bromine families. Reaction rates are governed by temperature, which depends on amounts of radiatively important species such as carbon dioxide. Human activities are increasing the amounts of these molecules and are thereby affecting the ozone layer. Evidence for anthropogenic ozone loss has been found in the Antarctic lower stratosphere. Near polar stratospheric clouds, chlorine and bromine compounds are converted to species that, when the Sun comes up in the southern spring, are broken apart by ultraviolet radiation and rapidly destroy ozone. This sudden loss of ozone is known as the anthropogenic Antarctic ozone hole. See also Stratospheric ozone.

ˈstræṭǝܖsfir n.the layer of the atmosphere above the troposphere, in which the change of temperature with height is relatively small.

See the Introduction, Abbreviations and Pronunciation for further details.

A layer of the earth's atmosphere, above the troposphere, 50 km in depth. Within the stratosphere, temperatures remain constant until the ‘ceiling’ of the stratosphere, the stratopause, is reached.

For more information on stratosphere, visit Britannica.com.

The region of the atmosphere of the Earth above the troposphere. The stratosphere begins at an altitude of seven to ten miles and extends to approximately thirty miles.

Buy Now

• Platform: IBM PC Compatible
• Release Date: January 07, 1997
• Genre: Strategy
• Style: Action Strategy

For other uses, see Stratosphere (disambiguation).

Atmosphere diagram showing stratosphere. The layers are to scale: from Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius. (click to enlarge)

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 word stratosphere is from the Greek meaning 'stratified layer' and sphaira meaning ball.

Contents 1 Temperature 2 Aircraft flight 3 Circulation and mixing 4 Life 5 See also 6 References 7 External links

Temperature

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 29.6°F), just slightly below the freezing point of water.^[1] 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.The major reason for the temperature increase with altitude is that most of the ozone (O₃) is contained in the stratosphere. High energy ultraviolet light interacts with ozone to cause the temperature increase.

Aircraft flight

Commercial airliners typically cruise at altitudes of 9–12 km in temperate latitudes, in the lower reaches of the stratosphere.^[2] They do this to optimize jet engine fuel burn, mostly thanks to the low temperatures encountered near the tropopause. It also allows them to stay above any hard weather, and 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. Although a few gliders have achieved great altitudes in the powerful thermals in thunderstorms, this is dangerous. Most high altitude flights by gliders use lee waves from mountain ranges and were used to set the current record of 15,447m (50,671 feet).

Circulation and mixing

This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (June 2009)

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.

Life

Bacterial life survives in the stratosphere, making it a part of the biosphere.^[3]

See also

• Léon Teisserenc de Bort and Richard Assmann (the discoverers 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

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2008)

1. ^ Seinfeld, J. H., and S. N. Pandis, (2006), Atmospheric Chemistry and Physics: From Air Pollution to Climate Change 2nd ed, Wiley, New Jersey
2. ^ Altitude of a Commercial Jet
3. ^ S. Shivaji et al, "Isolation of three novel bacterial strains, Janibacter hoylei sp. nov., Bacillus isronensis sp. nov. and Bacillus aryabhattai sp. nov. from cryotubes used for collecting air from upper atmosphere.", Int J Syst Evol Microbiol, 2009.

External links

Look up stratosphere in Wiktionary, the free dictionary.

v • d • e Earth's atmosphere Troposphere • Stratosphere • Mesosphere • Thermosphere • Exosphere Tropopause • Stratopause • Mesopause • Thermopause / Exobase Ozone layer • Turbopause • Ionosphere

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - stratosfære

Nederlands (Dutch)
stratosfeer

Français (French)
n. - stratosphère

Deutsch (German)
n. - Stratosphäre

Ελληνική (Greek)
n. - (μετεωρ.) στρατόσφαιρα

Italiano (Italian)
stratosfera

Português (Portuguese)
n. - estratosfera (f)

Русский (Russian)
стратосфера

Español (Spanish)
n. - estratosfera

Svenska (Swedish)
n. - stratosfär

中文（简体）(Chinese (Simplified))
同温层, 最高阶段, 最上层

中文（繁體）(Chinese (Traditional))
n. - 同溫層, 最高階段, 最上層

한국어 (Korean)
n. - 성층권, 최고단계

日本語 (Japanese)
n. - 成層圏

العربيه (Arabic)
‏(الاسم) الطبقه العليا من الغلاف الجوي‏

עברית (Hebrew)
n. - ‮סטרטוספירה - שכבת אטמוספירה המגיעה עד 05 ק"מ מפני הארץ‬

If you are unable to view some languages clearly, click here.

To select your translation preferences click here.