Download Chapter 4 Canadian Geography

Canadian Geography
Chapter 4 Climate
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 1. Weather- is the combination of
temperature, precipitation , cloud cover and
wind that we experience each day.
 Ex. 22 degrees , clear skies.
 Climate- is the long-term patterns of
weather conditions.
 Ex. Vancouver has an annual frost –free
period of 233 days.
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2. Five Factors that influence
climate:
 a. Latitude
 b. Air masses
 c. Altitude
 d. Landforms
 e. Nearness to water
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 2a. Latitude- how far north or south a
region is from the Equator influence how
cold or warm it is.
This is the most important thing that affects climate. All climate stems from the
equator (0° latitude). This is the hottest place on earth. As you go north or south
from this line it becomes colder as you travel towards the North and South
Poles.
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 Notes: the amount of heat energy, or
radiation, that the earth receives depends
on the angle of the sun’s rays.
 - if the angle creates a larger area than this
will cause a lowering of temperature.
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4. Earth’s Rotation Around the Sun
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 - the earth is tilted at an angle of 23.5
degrees.
 - the earth rotates around the sun every
365.25 days.
 - By June 21st , the Northern Hemisphere
is tilted toward the sun . This means that
the angle at which the sun’s energy
reaches places like Canada is less than at
other times of the year. Thus we receive
our warmest temperatures in the summer.
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 - By Dec 22nd the opposite occurs. The Northern
Hemisphere is pointed away from the sun thus
the angle the sun’s rays reach Canada is greater.
Thus we receive our coldest temperatures during
winter.
 Note:
 A. When the sun’s rays pass through the
atmosphere , it absorbs up to 15% of the
radiation.
 B. Heat energy is also reflected back into the
atmosphere as light . This reflectivity is called
albedo.
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Case Study : Seasons
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5. Air Masses
Air Mass – is a large body of air with a
uniform moisture and temperature
content. Whether an air mass is warm or
cold depends on where it originates.
- Each air mass has a two letter label. The
first letter indicates whether the air is wet ;
the second letter indicates the
temperature.
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 Note: Copy figure 4.8 pg. 52 into
notebook.
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
- Jet Stream- is a river of air that moves
from west to east at speeds between 300
and 400 k m/h , at an altitude between 8000
and
15 000 m.
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 - Most of the winds in Canada are called
Westerlies because they flow from west to
east.
 - The leading edge of an air mass is called a
front. Where two fronts meet often a
battleground is created . Air masses don’t mix
well.
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6. Cyclonic or Frontal
Precipitation
Precipitation is created when a warm , moist body of
air is forced to rise by a cooler body of air. As the air
rises , it begins to cool. Cold air does not hold
moisture as well as warm air . As, a result the water
vapour in the cooling air condenses into droplets.
These droplets form clouds and eventually they
become to heavy for the air to hold and thus fall as
rain or snow. ( Refer to pg.54 for diagram)
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7. Altitude
 Altitude or elevation , affects both
temperature and precipitation. Temperature
decreases as altitude increases. So the
farther up the air is from the ground , the
cooler it is. The temperature for , dry air
decreases 1 degrees C for every 100 m of
altitude.
 If the air is saturated with water vapour and
condensation forms , it retains more warmth .
This air cools down at a lower rate of 0.6
degrees C for every 100 m of altitude.
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 Chinook- is a warm wind that flows from the
Rocky Mountains across the foothills of
Alberta during the winter time.
 Chinooks—Warm West Winds
Along the eastern slopes of the Rockies, the Chinook
wind provides a welcome respite from the long winter
chill. Few people spend very much time along the
eastern slopes without experiencing these wonderful
warm winds. The change can be dramatic. On Jan.
11, 1983, the temperature in Calgary rose 30°C (from
–17°C to 13°C) in 4 hours.
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8. Landforms
 Landforms affect patterns of precipitation.
They sometimes create barriers for warm and
cold air reaching the land.
 A. Orographic or Relief Rainfall( Fig.4.18
p.59)
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 - This type of rainfall occurs when relatively
warm, humid air is forced to rise over an
elevated landform. (mountain)
 - Rain Shadow- is the dry side or leeward
side of a land mass.
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9. Nearness to Water
 Large bodies of water influence climate.
Water heats up and cools down more slowly
than land thus during winter the water is
warmer than summer in some areas.
 A. Moderated temperature- is a climate
created by the proximity of water that makes
land temperature milder in winter and cooler
in summer.
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 B. Maritime Climate- is a climate with a small
range between the maximum and minimum
monthly temperatures , usually found in
coastal locations.
C. Continental Climate- is a climate with a
large range between the maximum and
minimum monthly temperatures , usually
found in the center of large land masses.
 D. Temperature Range- is a calculation
made by subtracting the coldest temperature
from the warmest temperature.
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E. Land Breeze
 During the night air cools and descends and the cool air moves
seaward. Then the air above the water rises. ( Diagram p.61
right side)
1.Cool air over land sinks
2.Land Breeze moves out over water
3.Relatively warmer water heats air which then rises
4.Upper level return sea breeze
5.Cool air over land sinks
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F. Sea Breeze
 During the day the air is cooling and descending and the cool
air moves landward. The air is then heated over the land and
rises. ( Diagram p.61 left side)
1.Warm air over land rises
2.Sea Breeze moves inland
3.Cumuli develop aloft and move seaward
4.Upper level return land breeze
5.Cool air aloft sinks over water
6.Sea Breeze (meso-cold) Front
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10. Convectional Precipitation
Stage 1The sun heats the ground and warm air rises.
 Stage 2
As the air rises it cools and water vapour condenses to
form clouds.
Stage 3.
When the condensation point is reached large
cumulonimbus clouds are formed.
 Stage 4.
 Heavy rain storms occur. These usually include thunder
and lightening due to the electrical charge created by
unstable conditions.
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Is precipitation that occurs as a result of, warm
moist air rising , then cooling and creating
condensation . It often occurs on hot summer
afternoons and evenings.( refer p.63. diagram 4.24)
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 Animationhttp://62.239.5.6/vtc/Phase2deliv
ery/NCA/Geography/Keystage3/Weatheran
dclimate/Factorsaffectingweatherandclima
te/Factorsofweatherandclimate/Rainfall/De
fault.htm
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Terms:
 A. Hailstones- is an ice pellet formed when
a frozen raindrop is caught in violent updrafts
in the atmosphere.
B. Hurricane- is a massive storm that produces
heavy rain and winds exceeding 120km/h.
C. Tornadoes- is a destructive , rotating storm
under a funnel – shaped cloud that advances
across land at speeds of 50 to 100 km/h.
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 D. Climagraph- is a combined line and bar
graph showing average monthly temperature
and precipitation.
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