GEOGRAPHY AIR PRESSURE MAYANK FAUJDAR

2. What is Air Pressure?
It is the weight of the atmosphere pressing down on the earth.
It is measured by a barometer in units called millibars. Most
barometers use mercury in a glass column, like a thermometer,
to measure the change in air pressure.
WEIGHT OF THE ATMOSPHERE
MEASURED IN BAROMETER UNITS
MEASURE THE CHANGE IN AIR PRESSURE
BAROMETERS USE MERCURY
MERCURY IN GLASS COLOUMN I;e
THERMOMETER

3. Air Pressure
• Air pressure is the measure of the force with
which air molecules push on a surface.
• Air Pressure is GREATEST at the surface of
Earth because there is more of the
atmosphere above you to push down on you.

4. Barometer
• The piece of equipment used to measure
air pressure is a Barometer
Aneroid Barometer Mercury Barometer

5. PRESSURE BELTS
▸ Pressure belts indicate the horizontal distribution
of atmospheric pressure on earth's surface
▸ There are seven pressure belts in total, equatorial
low, two STHP belts, two SPL belts, two Polar high
belts

6. Wind Direction & Related Laws

7. Gradient Wind & Air Circulation
In atmospheric science, the pressure gradient
is a physical quantity that describes in which
direction and at what rate the pressure
increases the most rapidly around a particular
location.

8. •

12. These winds blow from sub tropical high
pressure belts towards sub-polar low pressure
belts. The westerlies of Southern Hemisphere
are more stronger and constant in direction
than Northern Hemisphere.
These winds develop be-
tween 40° and 65°S
latitudes and these latitudes
are known as Roaring
Forties, Furious Fifties and
Shrieking Sixties

14. These winds are
seasonal winds and
refer to wind systems
that have a
pronounced, seasonal
reversal of direction.
According to ‘Flohn’,
monsoon is a
seasonal modification
of general Planetary
Wind System.

16. These winds are
seasonal winds and
refer to wind systems
that have a
pronounced, seasonal
reversal of direction.
According to ‘Flohn’,
monsoon is a seasonal
modification of
general Planetary
Wind System.

17. The local difference in temperature and pressure causes
local winds. It is of four types: hot, cold, convectional and
slope