1. CLIMATE AND WEATHER
Section 2.3, p.33

2. Weather
The description of atmospheric conditions from day to day. (i.e. It’s sunny and warm today.)

3. Climate
This is the PATTERN of weather conditions over a long period of time. (i.e. July was not warm this year in NL.)

4. Global Factors
There are many factors about our Earth which control the weather and climate we experience in different regions.
Such factors include:
Latitude
Air Masses
Winds
Ocean Currents
Precipitation

5. 1. Latitude
Farther from the equator the average monthly temperature decreases because higher latitude locations get less direct sunlight.
Sunlight strikes these high altitudes at an angle.
Ex. Canada is, on average, colder than the USA

6. 2. Air Masses (p.34)
These are large bodies of air with predictable atmospheric features.
They move toward Canada and influence our weather and climate.
They are formed in certain places on Earth.
Where they form enables us to predict what they will bring.
Maritime Air Masses: form over the water (the air will be moist)
Continental Air Masses: form over
the land (the air will be dry)
Polar and Arctic Air Masses: form at
high latitudes (the air will be cool or
cold)
Tropical Air Masses: form near the
equator (the air will be warm or hot)

7. Combinations of Canadian Air Masses:
Maritime Tropical
(moist and warm air)
Maritime Polar
(moist and cold air)
Continental Arctic
(dry and cold air)
Continental Tropical
(dry and warm air) 3 2 2 1 4 1

8. 3. Winds
Wind – created by the uneven heating of the Earth by the Sun, as well as the Earth’s rotation (range from light breezes to natural hazards like hurricanes)
They generally blow eastward across Canada (from BC to NL)
This is the Coriolis Effect – because of the Earth’s rotation, wind in the Northern Hemisphere goes from west to east, while in the Southern Hemisphere the wind typically blows east to west.

9. Winds continued…
Canadian winds follow the direction of the high altitude wind called the jet stream
The jet stream always flows eastward, but changes its position and speed from summer to winter.
This is because the jet stream is created by the boundary between the cold Arctic air in the north, and the warm tropical air in the south.
The jet stream’s position changes as the difference in temperature becomes greater or lesser throughout the year.
The jet stream is strongest in the winter because it has the greatest difference in air mass temperatures as opposed to the summer when temperatures are closer in range of one another.
It moves slower and is found further north in the summer.

10. Jet Stream and Air Masses
After air masses arrive in Canada they move eastward following the path of the jet stream.
In the winter they move quickly and in summer they move more slowly
because the jet
stream is not as strong.

11. 4. Ocean Currents Four ocean currents affect Canadian climate:
2 east coast currents
A. The Labrador Current (cold)
B. The Gulf Stream Current (warm)
2 west coast currents
A. Alaska Current (warm)
B. North Pacific Current (warm)
***As a result of the flow of these currents, Canada’s west coast has a warmer climate because of the 2 warm currents. Notice what happens when the east coast currents meet off the coast of NL?!?!?!?! FOG!!!***
North Pacific (Warm)

12. 5. Precipitation Precipitation is a component of climate.
When warm air, carrying water vapour, rises, cools, and releases the vapour as precipitation.
Warm air is lighter than cold air and holds the most water vapour.
Depending on the air temperature, precipitation could be solid (i.e. snow) or liquid (i.e. rain).

13. Precipitation continued…
There are 3 general things that can force warm air to rise:
A. fronts of air masses
B. Convection
C. Mountains

14. Precipitation continued…
A. Frontal Precipitation
The leading edge of an air mass is called a front.
When the fronts with different air temperatures meet, warm air rises and precipitation is formed.
Cold Front Precipitation
You are located in an area with a warm
air mass
A cold front arrives and forces the warm air upward
Precipitation begins
Warm Front Precipitation
You are located in an area with a cold air mass
A warm front arrives and rises up over
the cold air

15. Precipitation continued…
B. Convectional Precipitation
Hot surface of the earth heats the air above it. The heated air expands and becomes lighter, therefore it rises.
Warm, light air rises and expands. Water becomes too heavy for the air to hold.
Cooler air is drawn in to replace the rising warm air.

16. Precipitation continued…
C. Orographic Precipitation
Wind forces warm air to rise up over a mountain.
This air cools, clouds form, and precipitation begins.
Notice the difference in the vegetation on both sides of the mountain

17. Canada’s Climate Regions
Canada is big enough to have several climate regions or zones.
They experience similar weather conditions.
Canada has 4 climate zones: Zone B, C, D, and E E C D B

18. Zone B Located in southern Alberta and Saskatchewan.
Here the climate is dry.

19. Zone C
This zone is found along the coast of British Columbia (including Vancouver Island).
The climate is warm and moist
Vancouver Island has a climate similar to that of southern Europe (i.e. Mediterrean)

20. Zone D This is the largest climate zone in Canada
Over 70%!
The climate is cool and moist
Most of this zone has precipitation throughout the year
The northern part of this zone has very short summers.

21. Zone E It is the second largest climate zone in Canada – about 25%
It’s located in the far north of Canada
Here the climate is very cold and dry.

22. Regional Factors
Climate regions may have features which make their weather unique.
These features include:
A. Altitude (elevation)
B. Bodies of Water
C. Mountain Barriers
At sea level, because the atmosphere above us is pressing down on the air below it, the air is denser because it is compressed (more oxygen concentrated at sea level). As we move to higher elevations, the air does not have as much weight pressing down on it, and as a result the air is ‘thinner’, and it becomes more difficult to breathe.

23. A. Altitude As altitude increases the air temperature decreases
Places with higher elevations are colder
The air is ‘thinner’ at high altitudes (oxygen levels)
COLD/LESS OXYGENATED
WARM/MORE OXYGENATED

24. B. Bodies of Water
Summer sunshine heats up land quickly and heats up water slowly.
In winter, land cools off quickly, but water cools off slowly.
Areas close to large bodies of water do not have big differences in climate change (i.e. moderate climate.
***Basically, temperature changes fluctuate way more over land than they do near bodies of water***

25. Bodies of water continued…
In Summer
•Land is warm
•Water is cold
•Summer is cool, not hot.
In Winter
•Land is cold
•Water is warm (finally, lol)
•Winter is mild, not cold.

26. Bodies of water continued…
Because they are near large bodies of water:
Places on the east and west coast of Canada have moderate climates.
Places near the Great Lakes have somewhat moderate climates
***Note: places far away from large bodies of water have much bigger changes on their climate throughout the year.***

27. C. Mountain Barriers
In Canada, almost all precipitation falls on the western slopes of large mountain chains.
Prevailing winds, traveling eastward, strike the western slopes first and drop their precipitation.
By the time the winds reach the other side of the mountain (eastern side) they are dry.
This effect is called
RAIN SHADOW.

28. Climograph In-Class Assignment
Handout: Climograph Construction and Analysis
Climograph Data: St. John’s
Month J F M A S O N D
Temp.
(Cel.) -4 -5 -2 2 6 11 16 18 13 8 4
Prec. (mm)
150
130
120
110
100 95 80
125
145

29. Climograph Data: Iqaluit
Climograph Data: Whitehorse
Month J F M A S O N D
Temp
(Cel.)
-25
-26
-23
-14 -3 3 8 7 2 -4
-12
-21
Prec. (mm 18 12 15 30 37 40 35 23
Month J F M A S O N D
Temp
(Cel.)
-18
-14 -7 7 12 14 11 8
-10 -5
Prec. (mm 18 15 30 37 40 35 23

30. In-Class Assignment
Handout: Factors that influence Climate

31. In-Class Assignment
Handout: Explain the climate conditions