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Structure of the earth's atmosphere

The mesosphere (from the Greek  μέση mésē “middle” and σφαίρα, sphaíra “sphere”) is the middle of the five layers of the earth's atmosphere as well as part of the ionosphere and the homosphere .

The mesosphere is delimited:

The mesosphere extends from about 50 km to 85 km in height.

When meteoroids enter the earth's atmosphere, they usually burn up in the mesosphere ( meteor ).

Temperature profile

Average temperature and molar mass of the air as a function of altitude

In the mesosphere, the temperature drops from around 0 ° C at the stratopause with seasonal fluctuations to an average of around −90 ° C at an altitude of around 80 kilometers, due to the extremely thin air and the fact that there is hardly any ozone left and the Absorption of the high-energy UV radiation only takes place in the underlying stratosphere. The temperature decrease in the mesosphere is, however, at around 3  K / km, considerably less than in the troposphere . Since the mesosphere is located above the ozone layer , the UV light here is still so strong that a human body would incur severe burns within a very short time. The mesopause, during which the temperature remains constant, lies above the mesosphere . It rises strongly again in the thermosphere, depending on solar activity up to 2,000 ° C.

In the mesosphere there is a circulation from the summer to the winter pole, which causes an upward transport of air masses in the area of ​​the summer pole and a downward transport in the area of ​​the winter pole. Due to the associated adiabatic cooling of the air (in the area of ​​the summer pole) or warming (in the area of ​​the winter pole), the mesosphere is significantly colder (by around 130 to 150 K) in summer (i.e. in the area of ​​the summer pole) than in winter.

Chemical composition

The chemical composition of the mesosphere, like that of the troposphere and the stratosphere, is fairly constant: its main components are nitrogen , oxygen , argon and carbon dioxide . The mesosphere is part of the homosphere .

Luminous night clouds

Luminous night clouds form in the upper mesosphere of the polar ice caps in summer . These can be seen with a bluish-silver shimmer with the naked eye even in moderate latitudes when they reflect the light of the setting sun. It is probably an accumulation of ice particles that should not be confused with the northern or northern lights and also not with the polar stratospheric clouds .

Web links

Wiktionary: Mesosphere  - explanations of meanings, word origins, synonyms, translations