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2. PRESSURE AND WINDS
PREPARED BY
BISWAJIT PAL
PGT GEOGRAPHY
KV KALIMPONG

3. KEY AREAS OF THE TOPIC
 Concept atmospheric pressure
 Types of atmospheric pressure
 Pressure belt
 General circulation of winds
 Other winds

4. LEARNING OUTCOMES
 What is atmospheric pressure
 What are the two types of atmospheric pressure
 What are different pressure belts
 What are atmospheric cells
 Relationship between pressure and winds

5. ATMOSPHERIC PRESSURE
Atmospheric pressure is
defined as the force per unit
area exerted against a surface
by the weight of the air above
that surface.
It can be measured with a
mercury barometer.
 The standard unit is millibar
The average pressure at sea
level is 1013.25 millibars.

6. TYPES OF ATMOSPHERIC PRESSURE
i. High pressure
ii. Low pressure

7. PRESSURE AND WINDS

8. HEAT ZONES AND PRESSURES
PRESSURE BELTS
ON THE EARTH:
1. Equatorial low
pressure zone
2. Subtropical
high pressure
zone
3. Sub polar low
pressure zone
4. Polar high
pressure zone

9. PRESSURE BELTS AND WINDS
Trade winds: Between the subtropical
high pressure zones and Equator
Westerlies: Between subtropical
high pressure zone and sub polar
low pressure zones
Polar Easterlies: Between polar
high pressure zone and sub polar
low pressure zones
Animated video link:
https://youtu.be/IGyjSLNyxXs

10. ATMOSPHERIC CELLS
1. Hadley cell
2. Ferrel cell
3. Polar cell

11. DIFFERENT TYPES OF WIND
Planetary winds
Seasonal winds
Local winds
Cyclones and anticyclones

12. PLANETARY WINDS
 Permanent wind in particular
region
 Example: Trade winds, Westerlies
and Easterlies
Video link: https://youtu.be/16-0UvOAjD8

13. SEASONAL WINDS
 Winds which blow in
particular season
 Eg, Tropical Monsoon
in India

14. LOCAL WINDS
 Winds which blow at a
particular place or
particular time of day
 Example: Loo, land
breeze and sea breeze
etc

15. LOCAL WINDS

16. LOCAL WINDS

17. CYCLONE AND ANTICYCLONE
 The wind
circulation around a
low pressure is
called cyclone.
 The wind
circulation around a
high pressure is
called anti cyclone.

18. RECAP
1. What is the average atmospheric pressure at sea level?
A. 986 mb B. 1012.25 mb C. 1013.25 mb D. 1023.25 mb
2. Westerlies are found between…………….
A. Equatorial low and subtropical high pressure zone
B. Subtropical high pressure and sub polar low pressure zone
C. Sub polar low and polar high pressure zone
D. None of the above
3. Which atmospheric cell lies between equatorial low and subtropical high pressure zone?
A. Hadley cell B. Ferrel cell C. Polar cell D. None of these.
4. Which of the following type of winds is Tropical Monsoon?
A. Planetary winds B. Seasonal winds C. Local winds D. Cyclone
5. Which of the following winds circulate around a high pressure?
A. Seasonal winds B. Cyclone C. Local winds D. Anti cyclone
Answer.
1. C
2. B
3. A
4. B
5. D
Live wind systems:
https://earth.nullschool.net/#current/w
ind/surface/level/orthographic=-
333.24,14.36,290/loc=118.168,6.948

19. THANK YOU