2. Content…………..
definition of atmosphere .
Composition of atmosphere and structures of
atmosphere
Content of atmosphere
Layer structures of atmosphere
Radiation and heat balance of atmosphere
atmosphere and oceans
3. DEFINITON
It is a mixture or combination of gases that surrounds the planet.
4. COMPOSITION OF ATMOSPHERE
Atmosphere is one of the most precious natural resources
Atmosphere is highly compressed at the lower levels ( it is very dense ).
The density of atmosphere is 1.2 kilogram per m3
When rising above to height of 500 m the density reduces 0.7 kilograms per m3
but physical geographers are only interested in the lower parts of the atmosphere
especially below 50 km and particulary below 10 km
The atmosphere extends from few meters below the ground on land and the water
surface in oceanic areas to a height of about 60000km above sea level .
5. DIVISION/LAYERS / STRUCTURES OF
ATMOSPHERE
Atmosphere is divided into two regions ;
• Hemisphere
• Heterosphere
1. HEMISPHERE ;
Lower region from the surface of 80 km – 100km above earths surface and this region has
/ less uniform of chemical composition
It is low region of atmosphere and it made up of troposphere and stratosphere
6. 2.HETEROSPHERE
This is air region of atmosphere with low / less concentration of gases
This is the layer above the hemisphere include ;mesosphere, and thermosphere / exosphere /
aonosphere and magnetosphere .
8. Groups of gases in the atmosphere
There are three major groups of gases that are found
in the atmosphere ;
Costant gases
variable gases
impurity gases
9. 1. COSTANT GASES
This gas found in the same proportions
constant gases are made up of 99 % of the air
It contains nitrogen and oxygen gases
nitrogen contains 78% of atmospheric air and it is converted by bacteria
into other nitrogen since it is not poisonous , it is also used for plant growth
and development .
on the other hand nitrogen accounts for 21% of atmospheric air , these
gases are used for burning food
It is for respiratory and also used for chemical processing such as , oxidation,
and combustions with fossil fuels .
10. 2.VARIABLE GASES
The proportional vary with time and space
These gases present in differing quantities at different times and
places .
They have tiny proportions of air and they are important to
human well being
examples of these gases are ; carbon dioxide , water vapor and
ozone
11. 3. IMPURITY GASES
These are aerosors and solid perticles in the industries
(tiny floating objects suspended in the atmosphere )
These impurity gases plays active role in the
atmosphere in the sense that it helps in development
of raindrops
Examples of impurity gases ; dust , smoke , bacteria
and plant spores .
12. ATMOSPHERIC CYCLES IN THE
ATMOSPHERE
There are four important atmospheric cycles
in the atmosphere
These are; 1. hydrogical cycle , oxygen cycle,
nitrogen cycle and carbon dioxide cycle .
1. HYDROGICAL CYCLE
14. 2. OXYGEN CYCLE
Oxygen is put back in the atmosphere as a by
product of photosynthesis
It is lost during respiration of animals or chemical
combinations with other materials during
oxidation.
15. 3. NITROGEN CYCLE
This is maintained by plants whose roots contain bacteria that can
extract nitrogen from the air or soil.
Nitrogen fixing bacteria convert atmospheric nitrogen into organic
compounds of the plants especially organic protein.
This protein may be transferred to animals when plants are eaten.
When animals and plants die, the nitrogen is transformed by bacteria
into ammonia, urea and nitrates and eventually back into gaseous
form of nitrogen which returns to the atmosphere.
16. 4. CARBON DIOXIDE
Dominated by exchange that occurs between the air and the oceans.
It enters the sea by direct absorption from the air, by plant and
animal respiration and by oxidation of organic matter.
Alternatively carbon dioxide is released from the ocean following
decomposition of plankton.
Another major exchange of carbon dioxide takes place between the
atmosphere and the plants of the biosphere.
17. VARIATION OF THE ATMOMOSPHERE
WITH HEIGHT
Water vapour comprises 4% of the total variation of the atmosphere
of the volume and 3% by weight
it is absent above 10- 12 kilometers
interms of layers it is concentrated between 15- 35 kilometers and it
found with the distance over 60 kilometers
18. Ways in which ozone formed
Ozone is formed from atom of oxygen , molecule of oxygen and
third particle of nitrogen
Ozone is formed form oxide pollutants as it reacts with sunlight
and destruction of ozone layer
It is formed through photodessociation during the day by uv
radiation
It is also formed through the reaction with nitrates and reactions
with chrolophrolocarbons
19. VARIATION OF ATMOSPHERE WITH
LATITUDES AND SEASONS
The ozone content is expected to be high at the equator because of polar
weight transport ozone
Water vapor content is greatest in summer and low latitudes
Carbon dioxide content the average atmospheric carbon is 315 parts per
million (ppm)
therefore, carbon content has high season variation in high altitude of the
northen hemsphere
Evidence ; at 50 north concentration of carbon ranges from 310 ppm in
late summer to 318 ppm in spring
20. VARIATION OF CARBON DIOXIDE WITH
TIME
It is produced by living organisms through respiration
By natural decay of organic element in the soil
By burning of a fossil fuels
Therefore carbon dioxide need to balanced in : carbon dioxide is
absorbed by the seas to produced carbonate of lime
Use of living organisms, the carbon dioxide can be balanced.
21. TOTAL PRESSURE OF THE ATMOSPHERE
Pressure is a measure of force exerted by air per unit area
It is measured in milibars
vapor pressure
The amount of water vapor in the atmosphere will depend on temperature
If temperature is high, there will be more water vapor and when the
temperature is low , there will be low water vapor
According to latitude, vapor is high in low latitude and it is low in high latitude
why it is so?
Because of the amount of solar energy received except where you have
23. The sun provides 99.97% of the energy required for all the physical process
that takes place on the earth surface and the atmosphere.
Absorbed insolation, radiant heat and input and output of radiation are
balanced at the planetary surface.
Radiation is a transmission of energy in the form of electromagnetic waves
Wavelength of radiation is the distance between two successive wave crests.
It varies with different types of radiation and is inversely proportional to
temperature of the body that sends it
the higher the temperature at which radiation is emitted, the shorter the wavelength of
the radiation.
24. 1. TROPOSPHERE
• It is the atmospheric zone where most events (such as cloud formation and rain
formation) occur.
• It is found up to an average altitude of 12km above sea level.
• The altitude of troposphere varies with latitude.
• It is lower in Polar Regions and higher above equator (8 - 16 in range).
• It is a region of both dry and wet lapse rates.
• That is to say the temperatures decrease with increasing altitude above sea level.
25. • The rate of decline of temperature (lapse rate) is 6.40
C/1000m (3.50
f/1000 ft).
• There are two breaks in troposphere which are characterized by regions of
variable rates.
• These are generally found at a latitude of about 25-50 North and South of the
equator.
• The breaks are associated with fast flowing winds – jet streams- in the upper
atmosphere which are important because through them, the troposphere and
stratosphere exchange materials and energy.
• Small amounts of water vapour find their way into the stratosphere and ozone
rich air is carried into the troposphere.
26. 2. STRATOSPHERE
• Above the troposphere is a calmer, thinner clear air of stratosphere.
• Jet aircrafts fly through its lower part as it provides easiest flying conditions.
• There is nearly total absence of clouds (H2O) hence fine visibility.
• As such, temperature increases with increasing altitude above sea level, thus
temperature inversion.
• Temperature inversion prohibits vertical winds so that the horizontal winds are
almost parallel to the ground ensuring fast and smooth flying.
27. • It is called Ozonosphere since it is where ozone is found.
• This ozone is produced naturally by action of ultraviolet sunlight on O2 and naturally destroyed
by green house gases.
• It is transported by natural processes.
• Transport and chemical reaction create a constant balance of stratospheric Ozone.
• Ozone shields the surface of the earth from ultraviolet radiation.
• At the same time absorption of ultraviolet rays by ozone heats the stratosphere giving it the
positive temperature rapes rate.
• Destruction of the ozone layer creates environmental concerns.
• The upper limit of the stratosphere is called the stratopause.
28. 3. MESOSPHERE
• Above the stratosphere, between 50km-80km there is the mesosphere.
• The temperature decreases with increasing altitude in the mesosphere.
• Over high latitude in summer the mesosphere display high wispy clouds that are presumed to
be sunlight reflected from meteoric dust particles that become coated with the ice crystals.
• Ionization occurs in this layer as sunlight reduces molecules to electronically charged particles
– ions.
• Ionized particles concentrates in a zone called D-Zone/layer which reflect radio waves sent
from earth’s surface in communication between ground and astronauts.
• The temperatures reduce with height to -90o
C at upper boundary/mesospause.
• The mesospause is about 80km above earth’s surface
29. 4. THERMOSPHERE
It is above 80km to 60 000km above surface.
Temperature rises spectacularly to 900o
C at 350km.
These temperatures apply to individual molecules as they are very far apart.
The molecules do not have the same environmental significance. Ionization occur in this part
producing two (2) more belts namely the E and F layer that reflect radio waves.
Intermittently, ionized particles penetrate the thermosphere, creating vivid sheet-like display of
light called aurora australis in Southern Hemisphere and aurora borealis in the Northern
Hemisphere.
In the upper thermosphere, there is further concentration of ions that comprise the Van Allen
radiation belts.
30. • This outer most layer is referred to the magnetosphere as earth’s magnetic force is
influential in movement of particles than the fore of gravity.
• There is no definable outer boundary and gradually blends into interplanetary
space.
• The air in this layer of low density consists of ions and light gases for instance
hydrogen and helium.
• The tiny ions of the gases in this layer absorb the shortest solar rays (ultraviolet
rays, x-rays and gamma rays).
• Temperature rises to 1200o
C (2200o
f).
• Thermosphere may extend out to some 1000km and gradually fades to the near
vacuum of space.
31. Radiation and heat balance of the
atmosphere
The sun provides 99.97% of the energy required for all the physical process that
takes place on the earth surface and the atmosphere.
Absorbed insolation, radiant heat and input and output of radiation are balanced
at the planetary surface.
Radiation is a transmission of energy in the form of electromagnetic waves
Wavelength of radiation is the distance between two successive wave crests.
It varies with different types of radiation and is inversely proportional to
temperature of the body that sends it
-the higher the temperature at which radiation is emitted, the shorter the wavelength of the
radiation.
32. The sun has surface temperature of 5 500o
C (6000o
K).
The earth’s surface has average temperature of 15o
C.
Therefore incoming radiation from the sun is shortwave radiation, and that emitted by the earth
is long wave radiation.
This electromagnetic spectrum ranges from very short waves such as Cosmic and gamma rays
to very long waves such as radio and electric-power waves.
33. Importance of atmosphere
Protection from solar radiation
Regulating temperature
Providing oxygen
Supporting weather patterns
Absorbing greenhouse gasses
