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Grade 10 Applied Science – Climate Change
Factors Affecting Canada’s Climate
There are four main factors that determine Canada’s climate:
 Mountain ranges and altitude
 Ocean currents
 Wind direction and the position of large bodies of water
 Latitude
1. Mountains – Altitude
 Higher you climb, colder it becomes
 Impacts precipitation – Air rises to get over the mountain. The air cools,
condenses and falls back to earth as rain or snow on the windward side of the
mountain. On the leeward side it is dry.
2. Ocean Currents
 A warm ocean current (1) brings moisture and (2) warms the nearby land (e.g.,
Pacific Ocean off B.C.).
 Cool ocean currents (1) cannot hold as much moisture and (2) cool the nearby
land (e.g., Atlantic Ocean off Labrador).
3. Wind Direction and Presence of Large Bodies of Water
 Air over water collects moisture. Over land, the air rises and cools, and the
moisture falls back to earth as rain or snow.
 Water warms and cools slower than nearby land. In the summer, water is cooler
than the land and the air temperature over the water is also cooler. The cool air
cools the nearby land. The water has a moderating effect on land temperature.
 Canada’s prevailing wind is from the west.
4. Latitude
 The further north from the equator, the colder it becomes. In the north, the sun’s
rays strike a very large area of the earth’s surface. The rays are not very intense,
and thus, the land is not warmed as much as at the equator.
Mountain Ranges and Altitude
The higher you climb (…or the higher the altitude…), the colder the air
temperature becomes.
Mountains also effect precipitation. More rain and snow fall on the windward
side of the mountain (…the side facing the oncoming winds). The leeward side
or “rain shadow” is drier.
On the windward side, the air rises and
cools as it travels up the side of the mountain. As the air
cools, it condenses and moisture falls back to earth as rain
or snow. On the leeward side, the air is dry. As a result,
there is little precipitation on the leeward side.
Ocean Currents
The ocean currents in the Pacific Ocean off British Columbia are warm. Warm air brings moisture
and also warms the nearby land. Ocean currents in the Atlantic Ocean along Labrador are cool.
Cooler air does not hold as much moisture as warm air. The cool air also keeps the nearby land
cool.
Wind Direction and Presence of Large Water Bodies
Air over a body of water collects water (i.e., evaporation). The
wind carries the moisture over the land, where the moisture may
fall as rain or snow.
Water also cools and warms slower than nearby land. In the
summer, the water is cooler than the nearby land. The air
temperature over the lake is also cooler. As the cool air mover
onto the land, it cools the land. In other words, the large body of
water has a moderating impact on the adjacent land.
Latitude
The equator is 0O. The further north or south from the equator you go, the colder it becomes.
The most southerly point of Canada is about 41oN near Point Pelee in Lake Ontario. Most of
Canada is north of 49oN. It is a long way north of the equator, and thus, it is cool.
The colder northern latitudes are due to the angle at which the sun’s rays strike the Earth. The
sun’s rays strike the equator in a very concentrated area, and thus, the rays only heat a small
area of the Earth’s surface. The heat energy
from the sun is very intense at the equator. In
contrast, the sun’s rays at higher latitudes
strike the Earth in a very spread out
area…due, in part, to the Angle of Incidence
(about 23O). Since the same amount of
energy in the sun’s rays must heat a larger
area, the area is cooler.
Angle of Sun’s Rays
The rays of the sun at mid-day are more
concentrated than is the case in early
morning, or in the later afternoon. It is warmer
at midday for this reason.
When the sun's rays strikes the earth
obliquely their energy is disseminated over a
wider area and does not warm our section of
the globe as do the more direct summer rays.
The same reasoning applies in the variation of
temperature during the day. As the sun rises
over the eastern horizon its rays strikes the
earth at an angle. As it rises higher in the
heavens the rays become more concentrated until at mid day they strike with their greatest force-their energy being concentrated in a comparatively smaller area. Then, as Old Sol sinks into the
west they rays gradually become less concentrated and intense, and it becomes cooler again.