atmosphere composition

8/10/2019 Atmosphere Composition

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TMOSPHERE

DEFINITION :

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained byEarth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect) , and reducing temperatureextremes between day and night. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95%oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air alsocontains a variable amount of water vapor, on average around 1%.

The atmosphere has a mass of about 5 10 18 kg, three quarters of which is within about 11 km(6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasingaltitude, with no definite boundary between the atmosphere and outer space. An altitude of120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry ofspacecraft. The Krmn line, at 100 km (62 mi), also is often regarded as the boundary betweenatmosphere and outer space.

Composition of dry atmosphere, by volum e [2]

ppmv: parts per million by volume (note: volume fraction is equal to mole fraction for ideal gas only, see volume

(thermodynamics) )

Gas Volume

Nitrogen (N2) 780,840 ppmv (78.084%)

Oxygen (O2) 209,460 ppmv (20.946%)

Argon (Ar) 9,340 ppmv (0.9340%)

Carbon dioxide (CO2) 390 ppmv (0.039%)

Neon (Ne) 18.18 ppmv (0.001818%)

Helium (He) 5.24 ppmv (0.000524%)

Methane (CH4) 1.79 ppmv (0.000179%)
http://en.wikipedia.org/wiki/Gaseshttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Organismhttp://en.wikipedia.org/wiki/Ultraviolethttp://en.wikipedia.org/wiki/Solar_radiationhttp://en.wikipedia.org/wiki/Greenhouse_effecthttp://en.wikipedia.org/wiki/Temperaturehttp://en.wikipedia.org/wiki/Daytime_(astronomy)http://en.wikipedia.org/wiki/Nighthttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Water_vaporhttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Atmospheric_reentryhttp://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_linehttp://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-1http://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-1http://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-1http://en.wikipedia.org/wiki/Parts_per_millionhttp://en.wikipedia.org/wiki/Parts_per_millionhttp://en.wikipedia.org/wiki/Parts_per_millionhttp://en.wikipedia.org/wiki/Volume_fractionhttp://en.wikipedia.org/wiki/Volume_fractionhttp://en.wikipedia.org/wiki/Volume_fractionhttp://en.wikipedia.org/wiki/Mole_fractionhttp://en.wikipedia.org/wiki/Mole_fractionhttp://en.wikipedia.org/wiki/Mole_fractionhttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Neonhttp://en.wikipedia.org/wiki/Neonhttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Neonhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Volume_(thermodynamics)#Partial_volumehttp://en.wikipedia.org/wiki/Mole_fractionhttp://en.wikipedia.org/wiki/Volume_fractionhttp://en.wikipedia.org/wiki/Parts_per_millionhttp://en.wikipedia.org/wiki/Atmosphere_of_Earth#cite_note-1http://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_linehttp://en.wikipedia.org/wiki/Atmospheric_reentryhttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Water_vaporhttp://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmospherehttp://en.wikipedia.org/wiki/Argonhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nighthttp://en.wikipedia.org/wiki/Daytime_(astronomy)http://en.wikipedia.org/wiki/Temperaturehttp://en.wikipedia.org/wiki/Greenhouse_effecthttp://en.wikipedia.org/wiki/Solar_radiationhttp://en.wikipedia.org/wiki/Ultraviolethttp://en.wikipedia.org/wiki/Organismhttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Gravityhttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Gases


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Krypton (Kr) 1.14 ppmv (0.000114%)

Hydrogen (H2) 0.55 ppmv (0.000055%)

Nitrous oxide (N2O) 0.3 ppmv (0.00003%)

Carbon monoxide (CO) 0.1 ppmv (0.00001%)

Xenon (Xe) 0.09 ppmv (9 10 6%) (0.000009%)

Ozone (O3) 0.0 to 0.07 ppmv (0 to 7 106%)

Nitrogen dioxide (NO2) 0.02 ppmv (2 106%) (0.000002%)

Iodine (I2) 0.01 ppmv (1 106%) (0.000001%)

Ammonia (NH3) trace

Not included in above dry atmosphere:

Water vapor (H2O) ~0.40% over full atmosphere, typically 1%-4% at surface

Earth's atmosphere can be divided into five main layers. These layers are mainly determined bywhether temperature increases or decreases with altitude. From lowest to highest , these layersare:

Troposphere The troposphere begins at the Earth's surface and extends up to 4-12 miles (6-20km) high. This is where we live. As the gases in this layer decrease with height,the air become thinner. Therefore, the temperature in the troposphere alsodecreases with height. As you climb higher, the temperature drops from about62F (17C) to -60F (-51C). Almost all weather occurs in this region.

The height of the troposphere varies from the equator to the poles. At the equatorit is around 11-12 miles (18-20 km) high, at 50N and 50S, 5 miles and at thepoles just under four miles high. The transition boundary between thetroposphere and the layer above is called the tropopause. Both the tropopauseand the troposphere are known as the lower atmosphere.

Stratosphere The Stratosphere extends from the tropopause up to 31 miles above the Earth'ssurface. This layer holds 19 percent of the atmosphere's gases and but very littlewater vapor.
http://en.wikipedia.org/wiki/Kryptonhttp://en.wikipedia.org/wiki/Kryptonhttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Nitrous_oxidehttp://en.wikipedia.org/wiki/Nitrous_oxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Xenonhttp://en.wikipedia.org/wiki/Xenonhttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Nitrogen_dioxidehttp://en.wikipedia.org/wiki/Nitrogen_dioxidehttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Water_vaporhttp://en.wikipedia.org/wiki/Water_vaporhttp://en.wikipedia.org/wiki/Water_vaporhttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Nitrogen_dioxidehttp://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Xenonhttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Nitrous_oxidehttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Krypton


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Temperature increases with height as radiation is increasingly absorbed byoxygen molecules which leads to the formation of Ozone. The temperature risesfrom an average -76F (-60C) at tropopause to a maximum of about 5F (-15C)at the stratopause due to this absorption of ultraviolet radiation. The increasingtemperature also makes it a calm layer with movements of the gases slow.

The regions of the stratosphere and the mesosphere, along with the stratopauseand mesopause, are called the middle atmosphere by scientists. The transitionboundary which separates the stratosphere from the mesosphere is called thestratopause.

Mesosphere The mesosphere extends from the stratopause to about 53 miles (85 km) abovethe earth. The gases, including the oxygen molecules, continue to becomethinner and thinner with height. As such, the effect of the warming by ultravioletradiation also becomes less and less leading to a decrease in temperature withheight. On average, temperature decreases from about 5F (-15C) to as low as -

184F (-120C) at the mesopause. However, the gases in the mesosphere arethick enough to slow down meteorites hurtling into the atmosphere, where theyburn up, leaving fiery trails in the night sky.

Thermosphere The Thermosphere extends from the mesopause to 430 miles (690 km) abovethe earth. This layer is known as the upper atmosphere.

The gases of the thermosphere are increasingly thinner than in the mesosphere. As such, only the higher energy ultraviolet and x-ray radiation from the sun isabsorbed. But because of this absorption, the temperature increases with heightand can reach as high as 3,600F (2000C) near the top of this layer.

However, despite the high temperature, this layer of the atmosphere would stillfeel very cold to our skin because of the extremely thin air. The total amount ofenergy from the very few molecules in this layer is not sufficient enough to heatour skin.

Exosphere

The Exosphere is the outermost layer of the atmosphere and extends from thethermopause to 6200 miles (10,000 km) above the earth. In this layer, atoms andmolecules escape into space and satellites orbit the earth. The transitionboundary which separates the exosphere from the thermosphere below it iscalled the thermopause.


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EPA Graphic

atmosphere composition

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