Download Unit 3 Lesson 6 Factors Impacting Climate

Grade 9 Geography - Unit 3 Lesson 6
Factors Affecting Canada’s Climate
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.
Factors Affecting Canada’s Climate…2
There are four main factors that determine Canada’s climate:
1. Mountain ranges and altitude
2. Ocean currents
3. Wind direction and the position of large bodies of water
4. Latitude
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.
Factors Affecting Climate …3
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.
Grade 9 Geogrpahy - Unit 3 Lesson 6
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.