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Gaseous layer that surrounds the planet Earth, is theoretically divided into several successive concentric layers. These are, from the surface to outer space: troposphere, tropopause, stratosphere, estratopausa, mesosphere and thermosphere.
The atmosphere is one of the most important components of the earth's climate. Is it the energy budget that primarily determines the state of the global climate, so it is essential to understand its composition and structure (GCCIP, 1997). The gases that are well mixed in the atmosphere is not physically uniform but it has significant variations in temperature and pressure associated with the height above sea level (GCCIP, 1997).
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The troposphere or lower atmosphere, which is in intimate contact with the earth's surface and extends to 11 km. s.n.m. on average (Miller, 1991). Has a thickness ranging from 8 km. at the poles to 16 km. in Ecuador, mainly due to the difference of energy budget in these places. Covers 75% of the total mass of gases that make up the atmosphere, 99% of the mass of the atmosphere is under 30 km. s.nm. (GCCIP 1997, Miller 1991). In particular, in 99% of two gases, nitrogen (N2, 78%) and oxygen (O2, 21%). The remaining 1% consists of argon (Ar, @ 1%) and Carbon Dioxide (CO2, 0035%). The air in the troposphere contains water vapor in varying amounts according to local conditions, for example, from 0.01% at the poles up to 5% in the tropics (Miller, 1991). The temperature decreases with height, on average, 6.5 ° C per kilometer. Most of the phenomena that occur involving the climate in this layer of the atmosphere (Kaufmann, 1968), partly supported by convective processes that are set by surface warming gases, they expand and rise to higher levels of the troposphere where cooled again (GCCIP, 1997). This layer also includes biological phenomena. The tropopause marks the upper limit of the troposphere, on which the temperature is kept constant before starting to increase again by about 20 km. s.n.m. This condition prevents thermal convection of air in this way and confined to the troposphere climate (GCCIP, 1997).
The layer above the tropopause where the temperature begins to rise is called the stratosphere, once they reach 50 km. height, the temperature reached 0 ° C. Therefore, extends from 20 km. up to 48-50 km. s.n.m. (Miller, 1991; GCCIP, 1997). Contains small amounts of gases in the troposphere in decreasing density proportional to height. It also includes very low amounts of ozone (O3) that filter 99% of ultraviolet (UV) radiation from the sun (Miller, 1991). Is this UV absorption which makes the temperature rise to about 0 ° C. This temperature profile allows the layer is very stable and avoid turbulence, something that characterizes the stratosphere. This, in turn, is covered by the estratopausa, a temperature inversion at 50 km. (GCCIP, 1997).
The mesosphere extends over 50 km., The temperature drops to -100 ° C to 80 km. above.
Over 80 km. asl, above the mesosphere, thermosphere extends, it continuously until the temperature is about 1000 ° C. For the low density of gases such altitudes are not temperature conditions comparable to those which exist on the surface (GCCIP, 1997).
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