The document discusses the composition and structure of Earth's atmosphere. It covers the following key points: - The atmosphere is composed primarily of nitrogen (78%) and oxygen (21%), with trace amounts of other gases like carbon dioxide, argon, and ozone. - The atmosphere is divided into five main layers - troposphere, stratosphere, mesosphere, thermosphere, and exosphere - with varying temperature and air pressure profiles. - The troposphere is the lowest layer where weather occurs. The stratosphere contains the ozone layer which absorbs harmful UV radiation from the sun. - The International Standard Atmosphere defines standard profiles for temperature, pressure, and other variables used in

2. METEOROLOGY CHAPTERS:
Atmosphere
Pressure
Density
Humidity
Temperature
Optical Phenomena
Winds
Rain/precipitation
Clouds
Visibility & Fog
Thunderstorm
Jet Streams
Clear Air Turbulence
Cyclones
Indian Climatology

3. CONTENTS :
INTRO TO THE ATMOSPHERE
COMPOSITION OF THE AIR
HOMOSPHERE & HETEROSPHERE
DRY AIR & SATURATED AIR
GREEN HOUSE EFFECTS
GREEN HOUSE GASES
LAYERS OF THE ATMOSPHERE
INTERNATIONAL STANDARD ATMOSPHERE
MULTI CHOICE QUESTIONS

4. •Atmosphere of the earth is an envelope of
homogenous mixture of gases called Air.
Air is a mixture of gases.
The atmosphere is the blanket of air that
surrounds the Earth.
Atmosphere has no upper limits.

6. Composition of the air :
Nitrogen
Oxygen
78%
21%
Other gases 1%

7. Other gases include :
Carbon dioxide
Argon
Traces of Neon, Helium, Methane,
Krypton,Hydrogen,Ozone,Xenon.

8. Nitrogen and oxygen constitute
almost 99% of the air. Their ratio
by proportion is :
Nitrogen:Oxygen 4:1 by volume.
Nitrogen:Oxygen 3:1 by weight.

9. Statistical representation of atmospheric
composition

10. Homosphere and Heterosphere

12. Dry Air & Saturated Air
Solid : Snow,hail,ice.
Liquid : Drizzle,rain,shower.
Gaseous : Water Vapour

13. Water Vapour

14. What is heavier ?
Cold Air or Hot Air
&
WHY

15. Carbon Dioxide
Why is it called Co2 ?
How is it produced ?
What is Photosynthesis ?

16. Green House Effect

17. Green House Gases

19. LAYERS OF THE ATMOSPHERE

20. The atmosphere is divided
into five layers. It is thickest
near the surface and thins out
with height until it eventually
merges with space.

23. 1. The Troposphere
•The lowest layer of the Earth's atmosphere.
.
•Temperature decreases as height increases (3.6
degrees/1000 ft). (6.5 celsius/km).
•Around the equator,the thickness is 16kms and
around poles it is about 8-10kms.
•ALL WEATHER occur in the Earth's
troposphere!

24. Troposphere is divided into 3 parts
Lower Troposphere : From surface to 2.1kms
Mid Troposphere : From 2.1kms to 7.6kms
Upper Troposphere : 7.6 kms onwards.

25. This is an image of the clouds in the Earth's troposphere.

26. 2. The Stratosphere
•The layer above the tropopause upto an Altitude of
50 km is called the stratosphere.
•Initially for 8-10 kms the layer is isothermal.
•Above it the temperature keeps on rising and is the
most at the top of the stratosphere layer.

28. Role of Ozone:
Ozone thus plays a key role in the
temperature structure of the Earth's
atmosphere.
Without the filtering action of the ozone layer,
more of the Sun's UV radiation would penetrate
the atmosphere and would reach the Earth's
surface.
The harmful effects of excessive exposure to UV
radiation.It causes harmful effect to crop,forest
growth and human health.

30. If ozone is decreased, it can
cause:
Skin cancer
Eye cataracts
Sun burning
Suppression of the human immune
system.
Adverse impact on crops and animals dueto
the increase of UV radiation

31. 3. The Mesosphere
•Temperature decreases with altitude. (30 – 55 miles)
•The atmosphere reaches its coldest temperature of
around -100°C in the mesosphere.
•Air pressure decreases.
•Does not have a lot of oxygen (at this level our
brain would be oxygen-starved called hypoxia.
•This is also the layer in which a lot of meteors burn
up while entering the Earth's atmosphere.

32. The space shuttle orbits in the
thermosphere of the earth.

33. 5. The Exosphere
•Very high up, the Earth's atmosphere
becomes very thin. The region where
atoms and molecules escape into space is
referred to as the exosphere.
•The exosphere is upper part of the
thermosphere.
•Extends about 550 km above the
surface.

34. This is a picture which shows the Earth, its atmosphere (the
clouds are likely in the troposphere and stratosphere).

35. Magnetosphere

36. International Standard Atmosphere
A standard average atmosphere has been
specified for various purposes like the
design and testing of aircraft, evaluation
of aircraft performance, calibration of
altimeters.

37. The most widely used atmosphere is the one
defined by the ICAO, known as the
International Standard Atmosphere (ISA). Its
specifications are;
Temperature at Mean Sea Level: 15 degree celsius.
Pressure at Mean Sea Level : 1013.25 hPa
Density at Mean Sea Level : 1225g/cubic metre.

38. Acceleration due to Gravity: 980.665cm
Lapse rate upto 11kms : 6.5 degree/km

39. MCQs

40. 1. Lowest layer of atmosphere is
called:
Troposhere Stratosphere

41. 2. Stratosphere extends from
Tropopause to :
50 KMS 60KMS 80KMS

42. 3. By volume, approximate ratio
of N2 to O2 in the atmosphere is :
4:1 3:1 5:1

43. 4. By weight, approximate ratio of
N2 to O2 in the atmosphere is :
4:1 3:1 5:1

44. 6. Which one of them is not a Green
House Gas ?
Methane CO2 Ozone

45. 7. Which gas is found in abundance in
the atmosphere?
Oxygen Argon Nitrogen

46. 8. According to the ISA, what is
the temperature at the Mean Sea
Level ?
16 degree celcius.
15 degree celcius
19 degree celcius

47. 9. What is the pressure at Mean Sea
Level?
1013.25 hPa 1011 hPa 2000 hPa

48. 10. Ozone is found in which layer?
Stratosphere
Exosphere
Mesosphere

49. THE END