1. TOPIC 3
1. HIGH AND LOW
PRESSURE
2. LAND AND SEA
BREEZES
TEXT PG 84-90

2. Essential
Questions
Definitions Learning
outcomes
A. What do high
pressure and
low pressure
areas refer to?
B. How are land
and sea
breezes
formed?
C. How are
monsoons
formed?
- Hot air rises in low
pressure areas and
cool air sinks in
high pressure
areas and winds
move from high
pressure to low
pressure areas.
- Monsoon winds
are results of
differences in
temperature
between large land
D. Explain how
coastal
temperatures are
moderated by
land and sea
breezes and why
the breezes move
in this particular
manner.
C. Explain the
formation of
monsoon winds.

3. 3A. What do high pressure and
low pressure areas refer to?
 Air pressure
◦ force exerted on a unit area of the earth’s
surface by the weight of a column of air above
it
◦ Measured by Barometer
 High Pressure
◦ Pressure above sea level value
 Low Pressure
◦ Pressure below sea level value
Sea level value of air pressure = 1,013mb

4. WIND
- Movement of air from an area of high
pressure to low pressure
- Measured in : Speed, direction,
frequency
Can you guess what are their
uses?
Wind rose Wind vane Anemometer

5. 3B. HOW ARE LAND AND
SEA BREEZES FORMED?
- LOCAL WINDS IN COASTAL AREAS
- LOWERS AND REGULATE THE
TEMPERATURE OF COASTAL AREAS
DURING DAY AND NIGHT
- RESULTS IN SMALLER DIURNAL
TEMPERATURE RANGE

6. Land and Sea breeze
Day Night
Land - Higher temperature
- Lower pressure
- Lower temperature
- Higher pressure
Sea - Lower temperature
- Higher pressure
- Higher
temperature
- Lower pressure
Breez
e
type
Sea breeze Land Breeze
Breeze
directio
From sea to land From land to sea

7. Draw diagram using text pg 87
3D. Explain how
coastal
temperatures are
moderated by
land and sea
breezes and why
the breezes
move in this
particular
manner.

8.  Regional wind patterns that reverse directio
seasonally
 Creates seasonal changes in rainfall
 Affected by Coriolis effect
◦ Force produced by earth’s rotation
◦ Changes the course of moving objects
◦ Eg bending or deflection of winds
Monsoon winds

9. Confusing Terms!
Southwest monsoon
 South = Australia
(High pressure)
 West = Direction of air
movement from high
(Australia) to low
(Indian subcontinent)
Northeast monsoon
 North = Indian
Subcontinent (High
pressure)
 East = Direction of air
movement from high
(Indian) to low
(Australia)
Australi
a
Australi
a

10. 3C. How are monsoons formed? Pg 88
Southwest monsoon Northeast monsoon
 During June and Sept
 Summer in North, Winter
in South
 Different pressures in Central
Asia and Australia
 Air from Australia moves to Indian
sub-continent and Central Asia
 Coriolis effect: deflects
winds to the right
 Forms southwest
monsoon winds and
warm air picks up
moisture
 Brings heavy rain to
 During Oct and Feb
 Summer in South, Winter in
North
 High pressure develops
over Indian sub-continent
and Central Asia, low in
Australia
 Dry and cold wind
 Coriolis effect deflects
winds to the left
 Forms northeast monsoon
winds and warm air picks
up moisture
 Brings heavy rain to

11. Homework 3
1. What do high pressure and
low pressure areas refer to?
[2]
2. How are land and sea
breezes formed? [2]
3. How are monsoons formed?
[3]