Prepared by {mehrabudin wakman}

Contact me

wakmanghfari@yahoo.com

Afghanistan

helmand

Objectives of this presentationObjectives of this presentation

1.Atmosphere.1.Atmosphere.

2.Layers of Atmosphere.2.Layers of Atmosphere.

3.Composition of the 3.Composition of the Atmosphere.Atmosphere.

4.Solid and liquid in 4.Solid and liquid in Atmosphere.Atmosphere.

5.Composition and pressure of 5.Composition and pressure of AIR.AIR.

AtmosphereAtmosphereAtmosphere

• thin layer of gases enveloping Earth

• no well-defined upper boundary – just fewer and fewer atoms

What is the Atmosphere?

View of the atmosphere

Is a mixture of different gasses. Is a mixture of different gasses. High above the planet it becomes High above the planet it becomes thinner until it becomes reaches thinner until it becomes reaches space. It is divided into five layers.space. It is divided into five layers.

Layers of the atmosphereLayers of the atmosphere

• There are 4 layers There are 4 layers in the atmospherein the atmosphere

• They are the They are the troposphere, troposphere, mesosphere, mesosphere, thermosphere, and thermosphere, and stratospherestratosphere

Temperature Layers from

Earth’s surface

1) Troposphere

2) Stratosphere

3) Mesosphere

4) Thermosphere

Not shown here –The Exosphere!

Let’s learn a little about each layer!

Troposphere

• This is the layer that is closest to the surface of the earth

• It’s elevation ranges from 0 to 10 km

TroposphereTroposphere

It is the first layer of Earths It is the first layer of Earths atmosphere, it is where all weather atmosphere, it is where all weather takes place and most clouds form.takes place and most clouds form.

• lowest layer; temperature decreases with altitude

• thinnest layer (8-16 km, avg. 11 km)• where weather occurs• primarily heated by Earth’s surface

Troposphere

StratosphereStratosphere

• This layer sits on top This layer sits on top of the troposphereof the troposphere

• It’s elevation ranges It’s elevation ranges from 10 km to from 10 km to around 25 kmaround 25 km

• This layer contains This layer contains the ozone layer, the ozone layer, which protects us which protects us from harmful from harmful sunlightsunlight

StratosphereStratosphere

The second layer of the atmosphere. The second layer of the atmosphere. Absorbs the ultraviolet rays and solar Absorbs the ultraviolet rays and solar radiation by use of the Ozone Layer.radiation by use of the Ozone Layer.

TropopauseTropopause

Between the troposphere and Between the troposphere and stratosphere.stratosphere.

MesosphereMesosphere

This layer is above the stratosphereThis layer is above the stratosphere

It’s elevation ranges from 25 to 100 kmIt’s elevation ranges from 25 to 100 km

Mesosphere

• above the stratosphere• temperature decreases with altitude• Meteorites and space dust burns up in this layer

MesosphereMesosphere

The third layer of the atmosphere. Is The third layer of the atmosphere. Is the coldest of the atmospheres and is the coldest of the atmospheres and is were most meteors are burned up in.were most meteors are burned up in.

Thermosphere Thermosphere • This is the highest This is the highest

layer of the layer of the atmosphereatmosphere

• It’s height ranges It’s height ranges from 100 to 400 kmfrom 100 to 400 km

• This is where most This is where most small meteorites small meteorites burn up and is also burn up and is also the location in the the location in the atmosphere that atmosphere that the northern lights the northern lights occur (aurora occur (aurora borealis)borealis)

Stratosphere

• found above the troposphere

• temperature rises with elevation

• Ozone Layer located here

• upper stratosphere temperature increases with altitude due to absorption of UV (ultraviolet) radiation in the ozone layer

Without the ozone layer protecting us, we could not live on the surface of the Earth!

Thermosphere

• above the mesosphere• temperature increases with altitude• contains a special part called the ionosphere

Composition of Atmosphere

atmosphere is a mixture of gases, solid particles, water

dropletsSmall changes are always

happening – physical processes (volcanoes),

– biological (plants and animals – transpiration and respiration),

major gases: N2 and O2

• lesser amounts of noble gases (Ar, Ne, Kr, Xe) • plus Hydrogen (H) and Helium (He) •N2:

• 78% volume

•O2: • 21% volume

Permanent Gases

• Water vapor (H20)• Carbon Dioxide (CO2)• Ozone (O3)

Variable Gases

source of this gas: evaporation from Earth’s surface• water cycle – moves water between oceans, land and atmosphere • 75% Earth’s surface covered by some form of water ground water• extremely important: clouds, absorb energy

Water VaporThis satellite image shows the relative amounts of water vapor: Dark – low water, white – high water vapor

•sources: respiration, organic decay, volcanoes, natural and man-made caused fires•important Greenhouse gas•More Carbon dioxide means more heating of the Earth

Carbon Dioxide (CO2)

Very emotional issue for Americans - Are we having a bad effect on the atmosphere of the Earth???

OzoneOzone (O(O33))

• consists of 3 O atoms (O2 + O = O3 )

• highest concentration in stratosphere

•shields surface from UV radiation • UV radiation splits O3 molecule

• also contributor to smog effects people and vegetation

Ozone LayerOzone Layer

Is in the stratosphere, protects Is in the stratosphere, protects earth from harmful solar earth from harmful solar radiation.radiation.

Solids and liquids in the atmosphere

• small solid particles and liquid droplets • associated with human and natural processes• larger particulate matter – dust, volcanoes, sea spray and combustion • major component of urban smog

Vertical Structure of the Atmosphere

• no clearly defined upper boundary

• density decreases with elevation

• We divide the atmosphere into layers based on:Changes in temperature

Density Density

• Gravity pulls the Gravity pulls the atmosphere downwardatmosphere downward

• atmosphere made up of atmosphere made up of gases which can be gases which can be compressedcompressed

• lower atmosphere greater lower atmosphere greater density density

Ionosphere

• defined based on electrical characteristics within the thermosphere

• absorbs cosmic rays, gamma rays, X-rays, some UV rays

• contains ions: charged electrical particles

• visible light is emitted when ions are bombarded by cosmic radiation produce aurora borealis, aurora australis

Composition of Air

There are many different types of gasses in the atmosphere

They include nitrogen, oxygen, argon, carbon dioxide and other noble gasses

The gas that is most abundant is nitrogen

Air Pressure

•atmosphere– exerts pressure

•the pressure is from the mass of the atoms •gravity – compresses air near surface (increase density) •felt by any surface in contact with air

•sea level pressure = 15 lb/in2

Air PressureAir Pressure