Climate

Weather:• Refers to the current, day-to-day, short term conditions of the atmosphere.

Weather:Wind speedWind directionTemperatureType of precipitationAmount of

precipitationCloud coverHumidityAir pressureHours of sunshine.

Climate:• Refers to the

long term trends / patterns in the weather for a certain area.

• Different areas experience different climate.

• Monthly, seasonal, yearly.

Do the following phrases refer to weather or climate?

• Annual precipitation of 200 mm.• Rain forecasted for tomorrow Tuesday.• Normal July temperature averages 22˚ C• Temperatures this week will range

between 20 & 30˚C

Do the following phrases refer to weather or climate?

• It was unusually hot this summer.• Grand Falls-Windsor had 15 cm of snow

this past weekend.• Vancouver has an annual frost free

period of 233 days.• Residents in Florida are preparing to

take shelter from a hurricane.

Sun’s energy is unevenly distributed across the earth’s surface

This heat imbalance sets the atmosphere and the oceans in motion

60% of the Sun’s heat energy is redistributed around the planet by Winds

40% by Ocean currentsPlaces located away from large bodies of water

have a continental climate (eg.. Swift Current, Saskatchewan)

Places located near the ocean have a maritime climate (eg.. Peggys Cove, Nova Scotia

Understand the cause of wind and how they affect climate

A wind is a horizontal movement of air across a surface.

Vertical movements are currents or updrafts and downdrafts

Caused by what????

Heat versus cold!!

Unequal heating Unequal heating causes pressure differences Cold, heavy air sinks = high pressureWarm, expanding air rises = low pressureWinds blow from high to low

The statement is fact. Think:

1. Air inside a balloon2. Exhaling3. Air powered pellet gun

It is simply fact. High and low pressures in the earth’s

atmosphere are responsible for wind

Wind:is a horizontal movement of air across a surface. It results from air masses of different temperatures and

humidity lying next to each other.The resulting pressure variation causes “wind” to blow

from high pressure areas to low pressure areas.

Prevailing Wind: Is regular, predictable, normal wind direction for a

given area or region. Caused by global convection cells. Named after the direction from which it comes

Winds

Prevailing

Air Masses

Large volumes of air with similar temperature and moisture

Continental Arctic – comes from Northern Canada and is COLD and Dry

Maritime Tropical – comes from the Caribbean and is WARM and WET

Maritime Polar – comes from Atlantic Ocean and is COOL and WET

They affect climate in Atlantic Canada because they bring to the characteristics of that particular air mass (See handout # 62 and Map Page 38)

North American Air Masses

Front

Leading edge of an air mass

Fronts, like air masses, bring the characteristics of the air mass that drives them and also sudden changes in weather

Atlantic Canada is mainly influenced by cold/dry air masses from north that meet warm/moist air masses from south

The point where the two air masses meet is called the front

Cold and Warm Fronts

During summer, Canada is affected by the warm, moist air from the Gulf of Mexico. This air mass pushes north giving us warm summer temperatures and precipitation.

During winter, air masses from Canada’s north dominate. The cold, dry air pushes south from the arctic

River of air moving from west to east at speeds between 300km\h – 400km\h at altitude between 8000 and 15000 feet. ( See Figure 4.11 and 4.14 page 54-55.

May move further north in summer bringing hot and humid conditions from the Gulf to Canada’s interior

May move further south in winter bringing bringing cold, dry air into Canada’s interior.