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PlanetPlanet BumiBumi

Earths

ATMOSFIR

Mengapa di Planet Bumi ada kehidupan ?

Apa yang akan terjadi kalau di luar planet bumi kosong

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The atmosphere is a mixture of different gases,

particles and aerosols collectively known as air which

envelops the Earth. The atmosphere provides various functions, not least

the ability to sustain life.

The atmosphere protects us by filtering out deadlycosmic rays, powerful ultraviolet (UV) radiation from

the Sun, and even meteorites on collision course with

Earth. Although traces of atmospheric gases have been

detected well out into space, 99% of the mass of the

atmosphere lies below about 25 to 30km altitude.

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Composition of the AtmosphereComposition of the Atmosphere

The atmosphere is primarily composed

of

Nitrogen (N2, 78%),Oxygen (O2, 21%), and

Argon (Ar, 1%).

A myriad of other very influentialcomponents are also present which

include the water

(H2O, 0 - 7%), "greenhouse" gases:Ozone ( 0 - 0.01%), Carbon Dioxide

(CO2, 0.01-0.1%),

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The Earths dry atmosphere is composed mainly of

nitrogen (N2, 78.1% volume mixing ratio),

oxygen (O2, 20.9% volume mixing ratio, and

argon (Ar, 0.93% volume mixing ratio).

These gases have only limited interaction with the incoming solar radiation and

they do not interact with the infrared radiation emitted by the Earth.

However there are a number of trace gases, such as carbon dioxide (CO2),methane (CH4), nitrous oxide (N2O) and ozone (O3), which do absorb and emit

infrared radiation.

These so called greenhouse gases, with a total volume mixing ratio in dry air of

less than 0.1% by volume, play an essential role in the Earths energy budget.Moreover the atmosphere contains water vapour (H2O), which is also a natural

greenhouse gas. Its volume mixing ratio is highly variable, but it is typically in the

order of 1%. Because these greenhouse gases absorb the infrared radiation

emitted by the Earth and emit infrared radiation up- and downward, they tend to

raise the temperature near the Earths surface. Water vapour, CO2 and O3 also

absorb solar short-wave radiation.

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IMPORTANT OF THE ATMOSPHEREIMPORTANT OF THE ATMOSPHERE

Protective blanket

Source of CO2 for plant photosynthesis Source of O2 for respiration Source of N2 for N fixing bacteria Basic part of hydrologic cycle

UNFORTUNATELYAtmosphere has been used as a dumping ground

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6/19Stratification of the AtmosphereStratification of the Atmosphere

BumiBumi dandan UdaraUdaraB

?

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TroposphereThe lowest layer of the atmosphere is called the troposphere.

It ranges in thickness from 8km at the poles to 16km over the

equator.

The troposphere is bounded above by the tropopause, a

boundary marked by stable temperatures. Above the

troposphere is the stratosphere. Although variations dooccur, temperature usually declines with increasing altitude

in the troposphere. Hill walkers know that it will be several

degrees cooler on the top of a mountain than in the valleybelow.

The troposphere is denser than the layers of the atmosphere

above it (because of the weight compressing it), and itcontains up to 75% of the mass of the atmosphere. It is

primarily composed of nitrogen (78%) and oxygen (21%) with

only small concentrations of other trace gases. Nearly all

atmospheric water vapour or moisture is found in the

troposphere.

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Stratosphere

The stratosphere is the second major layer of the atmosphere. It lies above

the troposphere and is separated from it by the tropopause. It occupies the

region of atmosphere from about 12 to 50 km, although its lower boundarytends to be higher nearer the equator and lower nearer the poles.

The stratosphere defines a layer in which temperatures rises with

increasing altitude. At the top of the stratosphere the thin airmay attain

temperatures close to 0C. This rise in temperature is caused by theabsorption of ultraviolet (UV) radiation from the Sun by the ozone layer.

Such a temperature profile creates very stable atmospheric conditions, and

the stratosphere lacks the air turbulence that is so prevalent in the

troposphere. Consequently, the stratosphere is almost completely free of

clouds or other forms of weather.

http://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Temperature.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Ozone_Layer.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Clouds.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Weather.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Weather.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Clouds.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Ozone_Layer.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Temperature.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.html

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Mesosphere

The mesosphere (literally middle sphere) is the third highest layer in our

atmosphere, occupying the region 50 km to 80 km above the surface of

the Earth, above the troposphere and stratosphere, and below thethermosphere. It is separated from the stratosphere by the stratopause

and from the thermosphere by the mesopause.

Temperatures in the mesosphere drop with increasing altitude to about -

100C. The mesosphere is the coldest of the atmospheric layers. In fact itis colder then Antarctica's lowest recorded temperature. It is cold enough

to freeze water vaporinto ice clouds. You can see these clouds if sunlight

hits them after sunset. They are called Noctilucent Clouds (NLC). NLCs

are most readily visible when the Sun is from 4 to 16 degrees below the

horizon.

The mesosphere is also the layer in which a lot of meteors burn up while

entering the Earth's atmosphere. From the Earth they are seen as

shooting stars.

http://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Stratosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Atmospheric_Layers.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Moisture.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Meteors.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Meteors.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Moisture.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Atmospheric_Layers.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Stratosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.html

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Ionosphere

The ionosphere is a layer of ionized air in the atmosphere extending from

almost 80 km above the Earth's surface altitudes of 600 km and more.

Technically, the ionosphere is not another atmospheric layer. It occupies

the same region of the upper atmosphere as the thermosphere. In this

region of the atmosphere the Sun's energy is so strong that it breaks apart

molecules and atoms of air, leaving ions (atoms with missing electrons)

and free-floating electrons. The ionosphere is the region of the atmosphere

where the aurorae occur.

Ionisation of airmolecules in the ionosphere is produced by ultraviolet

radiation from the Sun, and to a lesser extent by high-energy particles fromthe Sun and from cosmic rays.

The large number of free electrons in the ionosphere allows the

propagation of electromagnetic waves. Radio signals - a form of

electromagnetic radiation - can be "bounced" off the ionosphere allowingradio communication over long distances.

http://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Energy.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Aurora.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Cosmic_Rays.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Cosmic_Rays.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Aurora.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Energy.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.html

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Thermosphere

The thermosphere (literally "heat sphere") is the outer layer of the

atmosphere, separated from the mesosphere by the mesopause. Within

the thermosphere temperatures rise continually to well beyond 1000C.

The few molecules that are present in the thermosphere receive

extraordinary amounts of energy from the Sun, causing the layer to warm

to such high temperatures. Air temperature, however, is a measure of the

kinetic energy of air molecules, not of the total energy stored by the air.

Therefore, since the airis so thin within the thermosphere, such

temperature values are not comparable to those of the troposphere or

stratosphere. Although the measured temperature is very hot, thethermosphere would actually feel very cold to us because the total energy

of only a few air molecules residing there would not be enough to transfer

any appreciable heat to our skin.

http://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Mesosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Temperature.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Energy.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Stratosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Stratosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Troposphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Energy.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Temperature.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Mesosphere.html

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Exosphere

The exosphere is the highest layer of the atmosphere. Together with the

ionosphere, it makes up the thermosphere. The exosphere extends to

10,000 km above the Earth's surface. This is the upper limit of our

atmosphere. The atmosphere here merges into space in the extremely thin

air.Airatoms and molecules are constantly escaping to space from the

exosphere. In this region of the atmosphere, hydrogen and helium are the

prime components and are only present at extremely low densities. This is

the area where many satellites orbit the Earth.

At h R iAtmosphere Region

http://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Ionosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Air.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Thermosphere.htmlhttp://www.ace.mmu.ac.uk/eae/Atmosphere/Older/Ionosphere.html

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Atmosphere RegionAtmosphere Region

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Region of the atmosphereRegion of the atmosphere

TROPOPAUSE

STRATOPAUSE

MESOPAUSE

- 80 - 40 0 40 80 120

80

50

20 Heating from earth

Heating

By ozone

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Atmospheric pressure decreases

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OZON

Atmospheric pressure decreases

when moving from sea level to

higher altitudes in a very predictable

fashion. Atmospheric pressure is

the force gravity exerted on a unit ofair, by the mass of air directly above

it. The light blue line in Figure 32.1

illustrates how air pressure changes

with increasing altitude. The ScaleHeight equation is used by

meterologists to estimate

atmospheric pressure as a function

of altitude. The Scale Height

equation is:

where M = average molar mass of

air (28.92 g/mol), g = acceleration

due to gravity (9.78 m-s2), h =

height in meters, R = gas constant(8.314 J-mol-1-deg-1), and T is the

absolute temperature in Kelvins. Ph

represents the pressure at the new

altitude and Po represents theatmospheric pressure at sea level.

Earth's radiation budget expressed on the basis of portionsEarth's radiation budget expressed on the basis of portions

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Earth s radiation budget expressed on the basis of portionsEarth s radiation budget expressed on the basis of portions

of the 1,340 watts/m2 composing the solar f lux.of the 1,340 watts/m2 composing the solar f lux.

Atmospheric reactions involving the hydroxyl radicalAtmospheric reactions involving the hydroxyl radical

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Atmospheric reactions involving the hydroxyl radical.Atmospheric reactions involving the hydroxyl radical.

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