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::Troposphere

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convert}}, far above all three layers.)
File:EarthAtmosphereBig.jpg
Earth atmosphere diagram showing the exosphere and other layers. The layers are to scale. From Earth's surface to the top of the stratosphere (50km) is just under 1% of Earth's radius.

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and 99% of its water vapor and aerosols.<ref>McGraw-Hill Concise Encyclopedia of Science & Technology. (1984). Troposphere. "It contains about four-fifths of the mass of the whole atmosphere."</ref> The average depth of the troposphere is approximately {{safesubst:#invoke:convert|convert}} in the middle latitudes. It is deeper in the tropics, up to {{safesubst:#invoke:convert|convert}}, and shallower near the polar regions, approximately {{safesubst:#invoke:convert|convert}} in winter. The lowest part of the troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to {{safesubst:#invoke:convert|convert}} deep depending on the landform and time of day. The border between the troposphere and stratosphere, called the tropopause, is a temperature inversion.<ref name="DLA">Danielson, Levin, and Abrams, Meteorology, McGraw Hill, 2003</ref>

The word troposphere derives from the Greek: tropos{{#invoke:Category handler|main}} for "change" reflecting the fact that turbulent mixing plays an important role in the troposphere's structure and behaviour. Most of the phenomena we associate with day-to-day weather occur in the troposphere.<ref name="DLA"/>


Troposphere sections
Intro  Pressure and temperature structure  Atmospheric flow  Synoptic scale observations and concepts   See also   References  External links  

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