Download Unit 2 part 3 Winds

2.3 Winds
Understand the
cause of winds and
how winds affect
climate
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2.3.1 Define Prevailing Winds
Prevailing Wind
 Regular,
High
predictable, normal Low
wind direction.
 Caused by global
convection cells
when air blows
from high pressure
to low pressure
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2.3.2 Describe conditions that
results in Land Breeze
 Sea
air warmer
than land air
 Air rises over sea
 Relative Low
pressure over
sea
H
 Land air moves
to lower pressure
3
L
2.3.2 Describe conditions that
results in Sea Breeze
 Land
air warmer
than sea air
 Air rises over
land
 Relative Low
pressure over
L
land
 Sea air moves to
lower pressure
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H
Night Breeze
Night Breeze
Day Breeze
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2.3.3 State the impact of the Coirolis
Effect on wind direction.
 Objects
in motion
tend to deflect
 To the right in
northern
hemisphere
 To the left in
southern
hemisphere
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2.3.4 Infer how wind systems
relate to major pressure belts
 Air
rising from
the equator
 Settles at the
poles
 Result = 6
convection cells
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2.3.4 continued…
3
above and 3
below the
equator (low).
 Low pressures
result where hot
air rises.
 High pressures
result where air
8settles
2.3.4 continued
Global
highs and lows due to uneven
heating of the earth
Air moves from high pressure to low
pressure creating winds
Winds are deflected in the directions
indicated on the diagram due to the
coiriolis effect.
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2.3.4 continued
L
H
Equator Low
H
L
10
H
H
2.3.5 Explain how wind systems and
temperatures are related
How do the
prevailing winds
affect temperature
in:
1. Argentina
2. Columbia
3. Baffin Island
4. Newfoundland

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2.3.6 Define windward
The side of the
mountain facing
the wind
Windward
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2.3.6 Define Leeward
Mountainside
sheltered from
the wind
13
Leeward
2.3.6 Define Rain Shadow
Area with low
rainfall on the
leeward side of
the mountain
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Rain Shadow
2.3.7 Examine how the type of
rainfall is related to the nature of
location.
1. Orographic Rainfall
2. Frontal Rainfall
3. Convectional Rainfall
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1. Orographic rainfall
 Moisture
laden
air blows off the
sea
 Forced up by
mountains
 Air cools at
higher altitude
 Cool air holds
16less moisture
Chinook winds
1. Orographic Rainfall
 Clouds
condense and
rain falls
 Most rain falls
on the windward
side
 Leeward side is
often in a dry
rain shadow
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Rain Shadow
2. Frontal Rainfall
 Warm
moisture air
meets cold air
 Warm air is less
dense & is forced
up over the cooler,
more dense air
Warm
 Warm moisture air
Air
cools at higher
altitude
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Cold
Air
Weather Front
2. Frontal Rainfall
 Cool
air holds less
moisture
 Clouds condense
 Precipitation falls
Weather Front
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3. Convectional rainfall
 Forms
in tropics or
interior of continents
 Sun causes large
amounts of water to
evaporate
 Hot air rises forms
convection currents
(hence the name)
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Often associated with
thunderstorms.
3. Convectional rainfall
 Warm
moisture
air cools at higher
altitude
 Cool air holds
less moisture
 Clouds condense
 Rain falls
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2.3.8 Explain how wind systems and
precipitation
 How
do the prevailing winds affect
precipitation in:
1. England
2. Midwestern U.S.
3. British Columbia
4. Northern Africa
5. Central Australia
 Question #26 p. 67
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