2 What is Weather?The state of the atmosphere at any particular place or time. Described using such elements or variables as:1. temperature2. precipitation (type)3. humidity4. cloudiness5. air pressure6. wind speed and direction
3 Elements of Weather Wind Temperature Pressure Humidity Clouds Precipitation
4 WEATHERAlways 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 Collectingweather statistics statistical dataover periods of30 yearsStudy Climatology MeteorologyComponents precipitation, temp. Sunshine, rainhumidity, sunshine, cloud cover,wind velocity winds, hail,fog, frost, hail storms snow, sleet,over a period of time freezing rainflooding, blizzardsice storms, heatwaves
8 Effects on Climate Canada’s climate has so much variety because: It extends from a great distance from north to southDifferent elevationsCoastal and inland regions produce different climateWind and pressure systems move weather conditions from one part of the country to anotherSome 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) latitudeThis 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 coldThe 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 areaThe same amount of energy that hits the earth at the northerly location is spread over a larger area because of the curvature of the earthPlaces 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 surfaceMountain ranges act as barriers to the movement of air massesThis 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 climbAs the elevation gets higher, it gets colderAs 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 CLIMATEThe 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 CLIMATEThe 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 WaterBodies of water have a moderating effect on land temperaturesOceans and large lakes heat up and cool down more slowly than land massesIn summer, a body of water remains cooler than the land surrounding itWinds 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 WaterIn winter, bodies of water retain their heat and are warmer than the landWinds blowing off the water body warm the surrounding countrysideTherefore, 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 itOn the West Coast, the warm North Pacific Furrent heats the cools, moist air which passes over itThis gives a mild climate to the coastal regions of B.C.
20 Air MassesAir masses - a large volume of air with the climate conditions of the area where it is formedAir masses originating from oceans contain moisture. As the air passes over land, the moisture is released in the form of precipitationTherefore, maritime locations are more likely to receive more precipitation than inlandOn the other hand, air masses originating from a continental climate will be dry
21 Winds and Pressure Systems Air pressure - air that has weightDifferences in air pressure are created when the earth is heated to different temperaturesWarmed air rising above the heated ground creates an area of low pressureWhen 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 area2. The air cools and sinks. This produces a high-pressure area3. 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 areasPrevailing 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 airJet Stream - the current of fast-moving air located high in the atmosphere above the polar frontIn the winter this boundary between cold and warm air moves southward, allowing cold arctic air to flow farther southward into the United StatesIn the summer, it moves northward, allowing warm air from the Gulf of Mexico to flow farther northward in to Canada’s interiorThe 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