Climate
- Climate: a long-term pattern of weather
- Influences where we live, what farmers can grow, which clothes we wear, and how we construct buildings
- Keep in mind that Canada is very large (2nd largest country in the world), with varying levels of elevation and different coasts, so there are several factors that change the climate in different regions of Canada
- Latitude (North / South) affects climate / temperature as well
- Distance from the equator affects temperature and climate
- Relief: differences in elevation of the earth’s surface (mountain ranges act as barriers)
- the higher up a mountain you go, the colder the air gets (even though it technically puts you closer to the sun) due to air pressure
- Continental Environments: areas far from oceans and large lakes in the interior of land masses
- Has a great temperature range because there is no large water body to moderate the hot temperatures of summer and the cold temperatures of winter
- Maritime Environments: coastal locations (locations near bodies of water)
- Temperature range is relatively small and the level of precipitation is higher
- Moderating affect of Water:
- Oceans and large lakes heat up and cool down more slowly than land masses (summer water stays cooler, winter it stays warmer and wind influences where the heat/cold goes)
- Ocean Currents:
- The temperature of an ocean current affects the temperature of air that passes over it
- Air Masses: a large volume of air with the climate conditions of the area where it is formed
- Originating over an ocean contains moisture, which when it hits land is released as some form of precipitation (what does that mean about continental vs maritime environments?)
- Originating over a land mass will be dry because it is far form a large body of water
- Winds and Pressure Systems:
- Air Pressure: the weight that air has
- Differences in air pressure happen when the earth is heated to different temperatures
- Warm air rises (low pressure) then cools (high pressure) then repeats
- Wind: air moving along the surface of the earth from areas high-pressure to low-pressure areas
Precipitation
- Key points before we start talking about precipitation:
- Air cools as it rises
- As air cools, water vapour condenses more than it evaporates
- Air may rise for any of the following reasons:
- Rises to cross an area of high elevation (causes relief precipitation)
- Rises because it has absorbed heat from the earth’s surface (causes convectional precipitation)
- Rises because there is a cooler, denser air mass flowing beneath it that forces it up (causes cyclonic precipitation)
- Relief Precipitation (caused by mountain barriers)
- Moist air rises up the windward slope of a mountain range, then expands and cools
- As it cools, the rate of evaporation decreases while the rate of condensation increases (results in increased number of water droplets in the air, which combine to form raindrops)
- Condensation: process where water vapour cools and changes from a gas to liquid water
- When the raindrops become too large and heavy, they fall to the ground as rain (or snow)
- Relative Humidity: unit or amount that moisture content is measured in
- RH = (amount of moisture in air / moisture-holding capacity) x 100%
- What do you think dew or frost is?
- As the calm air on cool nights condenses on the ground / surfaces, it forms water droplets. If the temperature is below freezing, it forms ice crystals
- As cool air descends on the leeward slope of a mountain range, it contracts and becomes warmer
- Therefore, there’s more evaporation then condensation, so precipitation and cloud formation decreases
- Rain Shadow: very dry climate on the leeward side of a mountain range
- Convection Precipitation: formed due to convection (ground is heated, hot air rises then condenses and forms clouds)
- Common in summer in continental locations
- As more and more water condenses in the fluffy white clouds, they can rise higher and become much darker at the base (blocking the sun light)
- When the water condenses enough that the cloud can no longer support the weight, we get rain and / or a storm (figure 12-13 on page 136)
- Cyclonic Precipitation: caused by warm and cold fronts mixing
- A large, low-pressure storm that forms when a warm air mass and a cold air mass collide
- The rotation of the earth causes the air to circulate in a counter clockwise direction around an area of low pressure
Soil
- True Soil consists of four main parts:
- Minerals – minerals come from rock (parent material)
- Become a part of soil when rock is broken down by weathering into smaller particles of sand, silt, and clay
- Many of these minerals are nutrients needed by plants for growth (calcium, phosphorous, potassium)
- Bacteria and Organic Materials – when plants / animals die, they are decomposed by bacteria
- As organic matter is broken down by bacteria, nutrients are released
- Decaying organic materials form humus which provides nutrients and moisture for plants (gives soil its dark colour)
- Air – a high humus level helps produce air in the soil because the loose, decaying materials allow for many air pockets, and plants need air around their roots
- Worms, insects, and small animals which tunnel through the soil can also produce air pockets
- Moisture – water dissolves nutrients in the soil and is then taken up by plants through their roots
- Minerals – minerals come from rock (parent material)
- Soil Profile: different layers in the soil and rock layer below the soil. Each layer has different physical, biological, and chemical characteristics
- a basic soil profile has new minerals added at the bottom by weather of the parent material, then organic materials added at the top (topsoil)
- topsoil formation is a very slow process
- loam: a well-balanced mixture of sand, silt, and clay, plus humus
- the best soil for growing plants (encourages root growth and holds moisture, while allowing water to pass through it at a rate moderate enough to allow plants to take up nutrients)
- Leaching (moist climates): removal of minerals from soil by water as it moves downward through the soil (occurs in wet climates)
- areas with a great deal of precipitation have a continual downward movement of water through the soil
- this can take water soluble minerals so deep that plant roots cannot reach them
- has a poor, often thin topsoil layer
- however, can be developed into excellent farmland by adding fertilizers
- Calcification (dry climates): process by which, in dry climates, water carrying dissolved minerals moves upward through the soil. At the surface, the water evaporates, leaving the minerals behind (surface soil is now considered calcified)
- Capillary action: as water in the topsoil evaporates, water from below is drawn up to replace it.
- results in a thick topsoil that is very rich in nutrients
- called calcification because calcium is the main mineral deposited near the surface
- too much is a good thing: in very dry climates, the amount of mineral deposition can be so great that it forms a layer poisonous to plants.
- a basic soil profile has new minerals added at the bottom by weather of the parent material, then organic materials added at the top (topsoil)
Vegetation Regions
Natural Vegetation: plants that grow without any human interference
Transition Zones: area where the characteristics of one region gradually change into those of another
Transition Zones: area where the characteristics of one region gradually change into those of another
- Tundra: Marks the tree line (boundary between tundra and boreal forest, beyond which is too cold for trees to grow)
- Most of the tundra has permafrost (permanently frozen ground), with only the active layer (top layer) thawing during the short summer
- Very short growing season of small shrubs etc that grow close to the ground
- Very little humus
- Boreal and Taiga Forest: south of the tundra, the largest vegetation region in Canada
- Coniferous trees (trees with cones and needle-like leaves like an evergreen) in the Taiga forest
- Unsuitable for agriculture because of the lack of humus, high acidity, and the leaching effect of water
- Some Deciduous Trees (tree which sheds its leaves annually in the fall) can withstand the harsh winter conditions in the boreal forest
- Coniferous trees (trees with cones and needle-like leaves like an evergreen) in the Taiga forest
- Mixed Forest: vegetation region that contains both coniferous and deciduous trees
- wide variety of trees makes the mixed forest an excellent resource for the lumber industry
- however, due to lumbering, farming, urban development, and transportation routes, little of the forest remains in the southern part of the region
- soil is suitable for farming because of the rich soil and humus
- wide variety of trees makes the mixed forest an excellent resource for the lumber industry
- Deciduous Forest: found in southwestern Ontario
- long and hot summers with mild winters, and plentiful precipitation (ideal for hardwood trees)
- Soil is similar to mixed forest, but contains more humus and less acidic properties
- The most fertile soils of eastern Canada
- Grasslands (prairies): southern part of Manitoba, Saskatchewan, and Alberta
- Too dry for most trees, although some grow in river valleys where moisture is available
- Grass grows well, with the deep intertwined root system forming a sod mat (absorbs and stores moisture, and holds the soil in place)
- Grass dies on the surface, but the sod mat lives on and can sprout new grass when moisture returns
- Consists of 3 sub-regions:
- Short-grass prairie: driest areas of southern Saskatchewan and Alberta
- Drought resistant-short grasses, sagebrush, cactus etc
- Land is unsuitable for crops, but can be used for grazing animals
- Long-grass prairie: surrounds the short-grass prairie, an area of increased precipitation and taller grass
- Ideal for growing grains and oil seeds (seed used in the production of oils like canola or sunflower)
- The richest soil in Canada, that produces some of the best grains in the world
- Parkland: transition zone between the grassland and Boreal Forest, found between the long- and short-grass prairies
- Short-grass prairie: driest areas of southern Saskatchewan and Alberta
- Cordilleran Vegetation: varies greatly because of the temperature change between valleys and mountain tops, and the abundant rainfall on the west side of a mountain as opposed to the east side
- Elevation also changes the kind of vegetation that can be grown
- Coniferous trees grow on lower slopes where precipitation is heavier (important for logging community in BC)
- Vegetation on higher slopes resembles that of the tundra
- Elevation also changes the kind of vegetation that can be grown
- West Coast Forest: a lush forest of Douglas fir, Sitka spruce, red cedar, and western hemlock grow along the West Coast of Canada
- Excellent growing conditions are provided by the heavy rainfall and mild climate
- These trees have played a major role in the forest industry of BC