Factors that Influence Climate

a.k.a.

LOWER near water

LOWER Near Water

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

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.

fog

Labrador Current

Gul

f Stre

am

Winds and Air Masses

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

CT Hot Dry

Maritime Tropic

mT Warm Moist

Maritime Polar

mP Cool to cold Moist

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.

Relief: As air is forced over mountain barriers, it cools and creates precipitation.

Alti

tude

(m

)

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

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

•Yellowknife -5.2ºC

•Point Pelee 9.1ºC

LATITUDE

Which factor accounts for these differences in annual precipitation?

•Regina 526 mm

•Toronto 989 mmNEAR WATER

Which factor accounts for the lack of vegetation on one side of the mountain?

RELIEF

The leeward side of themountain (away from thewind) is warmer and drier than the windward side causing less vegetation to grow.

Direction of wind

Which factors account for these differences in average annual temperature and precipitation?

•Vancouver10ºC, 1100 mm

•St. John's5ºC, 1500 mm

OCEAN CURRENTS

WARMNORTHPACIFICCURRENT

COLD LABRADORCURRENT

LATITUDE WINDS

Which factor accounts for the difference in average maximum July temperature?

sealevel

Calgary 16.1ºC Kamloops 20.9ºC

ELEVATION