1. CLIMATE and WEATHER

2. What is Weather?
The state of the atmosphere at any particular place or time. Described using such elements or variables as:
1. temperature
2. precipitation (type)
3. humidity
4. cloudiness
5. air pressure
6. wind speed and direction

3. Elements of Weather Wind Temperature Pressure Humidity Clouds
Precipitation

4. WEATHER
Always changing, exhibiting large fluctuations in the atmosphere from hour-to-hour or day-to-day

5. What is CLIMATE?
climate is defined as an area's long-term weather patterns. The simplest way to describe climate is to look at average temperature and precipitation over time. Other useful elements for describing climate include the type and the timing of precipitation, amount of sunshine, average wind speeds and directions, number of days above freezing, weather extremes, and local geography .

6. What is CLIMATE?
Climate is the average weather in a place over many years. While the weather can change in just a few hours, climate takes hundreds, thousands, even millions of years to change.

7. Weather vs Climate Climate Weather
Forecast: By aggregates of Collecting
weather statistics statistical data
over periods of
30 years
Study Climatology Meteorology
Components precipitation, temp. Sunshine, rain
humidity, sunshine, cloud cover,
wind velocity winds, hail,
fog, frost, hail storms snow, sleet,
over a period of time freezing rain
flooding, blizzards
ice storms, heat
waves

8. Effects on Climate Canada’s climate has so much variety because:
It extends from a great distance from north to south
Different elevations
Coastal and inland regions produce different climate
Wind and pressure systems move weather conditions from one part of the country to another
Some very large lakes, such as the Great Lakes, also have an effect

9. Effects on Climate: Latitude
The most southerly point in Canada is Pelee Island in Lake Erie (41ºN)
The most northerly point in Canada is Alert (Ellesmere Island) (83ºN) latitude
This large range in latitude has a major impact on Canada’s climate

11. Effects on Climate: Latitude
distance from the equator is a key factor in whether a region is hot or cold
The size of the land mass in which a region is located is also a factor

12. Effects on Climate: Latitude
The energy from the sun that hits the earth at the equator covers a small area
The same amount of energy that hits the earth at the northerly location is spread over a larger area because of the curvature of the earth
Places closer to the North and South Poles experience colder temperatures

13. Effects on Climate: Relief and Elevation
Relief refers to differences in elevation of the earth’s surface
Mountain ranges act as barriers to the movement of air masses
This is why Vancouver often has warm, rainy weather in winter, while Calgary, on the other side of the Cordillera, has cold, dry weather

14. Effects on Climate: Latitude
If you were hiking to the top of a mountain, you would notice that the temperature drops steadily as you climb
As the elevation gets higher, it gets colder
As air rises, it expands because there is less air pressure. As the air expands, it loses heat

15. Continental Environments
Areas far from oceans and large lakes in the interior of land masses have a CONTINENTAL CLIMATE
The temperature range is great because there is no large body to moderate the hot temperatures of summer and the cold temperatures of winter

16. Maritime Environments
Coastal locations have a MARITIME CLIMATE
The temperature range between the highest average monthly temperature and the lowest average monthly temperature is relatively small and the level of precipitation is higher

17. The Effect of Water
Bodies of water have a moderating effect on land temperatures
Oceans and large lakes heat up and cool down more slowly than land masses
In summer, a body of water remains cooler than the land surrounding it
Winds blowing from over the water keep the surrounding countryside cooler than it would be if the water body was not present

18. The Effect of Water
In winter, bodies of water retain their heat and are warmer than the land
Winds blowing off the water body warm the surrounding countryside
Therefore, maritime locations near a large body of water, have cooler summers and milder winters than continental locations

19. Ocean Currents Climate is affected by ocean currents
The temperature of an ocean current affects the tempeature of air that passes over it
On the West Coast, the warm North Pacific Furrent heats the cools, moist air which passes over it
This gives a mild climate to the coastal regions of B.C.

20. Air Masses
Air masses - a large volume of air with the climate conditions of the area where it is formed
Air masses originating from oceans contain moisture. As the air passes over land, the moisture is released in the form of precipitation
Therefore, maritime locations are more likely to receive more precipitation than inland
On the other hand, air masses originating from a continental climate will be dry

21. Winds and Pressure Systems
Air pressure - air that has weight
Differences in air pressure are created when the earth is heated to different temperatures
Warmed air rising above the heated ground creates an area of low pressure
When the rising air has cooled, it falls toward the earth and creates an area of high pressure

22. Winds and Pressure Systems
Heating of the ground by the sun warms the air above it and causes the air to rise. This produces a low-pressure area
2. The air cools and sinks. This produces a high-pressure area
3. Air at ground level moves from high pressure to low pressure, creating winds

23. Winds and Pressure Systems
Wind - moving air caused by the high-pressure areas moving toward low-pressure areas
Prevailing winds - high and low-pressure belts that have created a pattern of winds. a.k.a. “westerlies’. They move in air masses that affect our weather

24. Winds and Pressure Systems
POLAR FRONT - the boundary between cold, dry polar air and warm, moist tropical air
Jet Stream - the current of fast-moving air located high in the atmosphere above the polar front
In the winter this boundary between cold and warm air moves southward, allowing cold arctic air to flow farther southward into the United States
In the summer, it moves northward, allowing warm air from the Gulf of Mexico to flow farther northward in to Canada’s interior
The warm air masses and the cold air masses that meet at the polar front do not mix easily. Instead they often enter into a battle in the sky that we see as a storm