Structure of the atmosphere

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Troposphere

Stratosphere

Mesosphere

Thermosphere

This is the lower part and most dense layer of the atmosphere.

Most of the turbulence occurs in this layer, all clouds, precipitation, and storms are developed.

The troposphere is wider at the equator about lower 10 to 12 km or 6 to 8 mi. than at the poles with 5 to 8 km or 5 mi.

The air temperature falls until -55º C at the upper boundary at about 12.8 km, known as the tropopause, in middle latitude.

It contains 75 percent of the Atmosphere’s mass- on an average day the weight of the molecules in air is 1.03 kg./sq. cm. and most of the atmosphere’s water vapor.

The most prevalent gases are nitrogen(78%) and oxygen(21%), with the remaining (1%) for argon, traces of hydrogen, ozone, methane, and other constituents.

A common feature of the troposphere of densely populated areas is SMOG.

Upper layer of the atmosphere commencing at an altitude of 24 km and extending upward to about 40-48km.

In the lower portion of the stratosphere, the temperature remains nearly constant with height, but in the upper portion the temperature increases rapidly with height about -10ºC because of absorption of sunlight by ozone.

The stratosphere is almost completely free of clouds or other forms of weather.

The coldest layer of the atmosphere with altitude to about -95ºC at the upper boundary of 80-96 km altitude, known as mesopause.

On this region where the lowest temperature in the atmosphere is found.

The presence of “Noctilucent Clouds” is a high distinguishing feature of this layer.

The air temperature decreased with height.

80 km. and up. The air is very thin.Thermosphere means heat sphere.The temperature on this layer is very high

because the ultraviolet radiation is turned into heat.

Temperature often reach 2000 degree Celsius or more.

This layer contains IONOSPHERE, and EXOSPHERE.

It is the lower part of the thermosphere.It extends from about 80km to 550 km.The particles of gas become electrically charged (ions). Radio waves are bounced off the ions and reflect waves back to earth. This generally helps radio communication. However, solar flares can increase the number of ions and can interfere with the transmission of some radio waves. 

The upper part of the Thermosphere.It extends from about 550 km for thousands

of kilometers.The air is very thin here.This is the area where satellites orbit the

earth.

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