Factors that Influence Climate
a.k.a.
LOWER near water
LOWER Near Water
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L for Latitude
O for Ocean Currents
W for Winds and air masses
E for Elevation
R for Relief
Near Water
Latitude

The earth's curvature causes the sun's energy to be
less concentrated at the poles than near the equator.
Latitude

Places closer to the equator are warmer than
places further north or south

Warmer air can hold more moisture than
colder air; therefore, areas further away from
the equator are drier than areas closer to the
equator.
Ocean Currents

An ocean current (like a river within the
ocean water) can be warmer or cooler than
the water around it.

Air above the water is affected by the
temperature of the water as it passes over.
West Coast Current


The west coast has
a warm ocean
current called the
North Pacific
Current
Brings warm, moist
air to the Pacific
coastal areas
East Coast Currents


fog

The cold Labrador
Current flows from the
north along the coast of
Labrador
The warm Gulf Stream
flows from the south
along Nova Scotia and
Newfoundland
Where they meet, fog is
created.
Winds and Air Masses
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An air mass is a large volume of air that has
the temperature and humidity of the location
where it was formed.
If it formed over an ocean, it's wet. If it
formed over land, it's dry.
If it formed in the north, it's cold. If it formed
in the south, it's warm.
Winds and Air Masses



Winds blow these air masses from one
location to another.
In Canada, most of our winds (the prevailing
winds) come from the west. They are called
the "Westerlies".
The Westerlies are controlled by the jet
stream (a current of fast-moving air high in
the atmosphere).
Winds and Air Masses



North of the jet stream
it is colder than south of
the it.
In the summer, the jet
stream moves
northward, so we get
warmer weather.
In the winter, the jet
stream moves further
south and we get colder
weather.
(Textbook Fig. 12-7 is similar)
Air Masses are named for whether they
formed over land or water and whether they
formed in the north or the south.
Air Mass
Initials
Temperature
Moisture
Continental
Arctic
CA
Cold to very cold
Dry
Continental
Tropic
Maritime
Tropic
CT
Hot
Dry
mT
Warm
Moist
mP
Cool to cold
Moist
Maritime
Polar
Elevation




Elevation is the height the land is above sea
level.
As air rises, it expands due to the decrease
in air pressure.
As air expands, it cools.
Since colder air cannot hold as much
moisture (water vapour) as warmer air, when
the air cools, the water vapour condenses
into liquid water droplets.
Elevation



Once the droplets are big enough, they will
fall as rain or snow, depending on the
temperature.
Summary: Areas lower in elevation tend to
be warmer than areas higher in elevation.
This factor is not dependent on how the land
is shaped. An area of flat land at a higher
elevation is colder than an area of flat land at
lower elevation.
Altitude (m)
Relief: As air is forced over mountain barriers,
it cools and creates precipitation.
The windward side of the
mountain is wetter and the
leeward side is drier.
Near Water


Areas that are close to water have their climate
moderated by the water so that the summer
temperature are not as hot and the winter
temperatures are not as cold.
Creates maritime climates near water and
continental climates away from water
"Lower near water"
Urban Areas

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All previous factors were natural. The last
factor that influences climate is man-made.
Areas in and near large cities have higher
temperatures due to the fact that the
pavement, cars and buildings absorb and
reradiate more of the sun's energy than
natural areas.
Areas downwind of cities tend to have more
precipitation because the pollution particles
from the city act as nuclei for water droplets.
Which factor accounts for these different
average annual temperatures?
•Alert -18.1ºC
LATITUDE
•Yellowknife -5.2ºC
•Point Pelee 9.1ºC
Which factor accounts for these
differences in annual precipitation?
•Regina
526 mm
NEAR WATER
•Toronto
989 mm
Which factor accounts for the lack of
vegetation on one side of the mountain?
RELIEF
Direction of wind
The leeward side of the
mountain (away from the
wind) is warmer and drier
than the windward side
causing less vegetation to
grow.
Which factors account for these differences in
average annual temperature and precipitation?
LATITUDE
WINDS
COLD
LABRADOR
CURRENT
WARM
NORTH
PACIFIC
CURRENT
•St. John's
5ºC, 1500 mm
•Vancouver
10ºC, 1100 mm
OCEAN CURRENTS
Which factor accounts for the difference
in average maximum July temperature?
Kamloops 20.9ºC
Calgary 16.1ºC
sea
level
ELEVATION