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CGC 1D We live in a World of Systems Factors Affecting Climate There are six factors that affect climate in Canada. “MALOOP” M = Mountains A = Altitude L = Latitude O = Ocean Currents O = Open Bodies of Water P = Pressure Systems & Winds Mountains 1. Mountains block winds and create various climate effects. In Canada the Western Cordillera mountain ranges block the moist, warm air from the ocean getting to the prairies. They create relief (orographic) precipitation. 2. South facing slopes on mountains are warmer than north facing slopes (micro-climates). cooling, condensation & precipitation rising air South facing slope Altitude The height above sea level. The higher you go the colder it gets. Why? 1. The atmosphere is thinner with less gas molecules per volume. The molecules are spread out and radiate less heat. 2. The higher you go the further you are from the heat radiating out from the earth. For every 100 m up the temperature drops 1 ºC. Latitude The further from the equator, the colder it gets. For example: 45ºN, is colder than 25ºN. 52ºS is colder than 45ºS. Why? CGC 1D We live in a World of Systems Atmosphere Earth 1. At latitudes further from the equator the sun’s rays coming in at a lower angle and hit the surface of the earth and therefore have to cover a larger area (so less intense heating). 2. Also, at higher latitudes, rays pass through a greater distance of atmospheric gases. There is a greater chance of reflection and absorption on their way to the earth. Ocean Currents The temperature of an ocean current affects the temperature of the air mass that passes over it. West Coast of Canada “North Pacific” Current (is warm) This current heats the cool moist air that passes over it This makes the climate of coastal B.C. very mild. East Coast of Canada The cold “Labrador Current” (flows south from the Arctic) It cools the air above it (Nova Scotia and Newfoundland) The warm “Gulf Stream or North Atlantic drift” flows up the eastern NA coast from Mexico. When these two air masses (Cold and Warm) meet off the coast of NS, NL & NB the weather is damp and vision is impaired due to fog. CGC 1D We live in a World of Systems Open Bodies of Water (unfrozen water) Just being close to, or far away from, an open body of water will have an effect on climate. Being close to an open body of water, keeps climate milder in the winter and cooler in the summer. The land heats up more quickly, and cools down more quickly than water. Any winds blowing over the water will bring the warmth or coolness of the water on to the shore. Therefore: In summer, land will get a cooling effect from near-by water. In winter, the land will get a warming effect. The further away from the water, the less effect the water will have. This is called the moderating effect. Results: Maritime Climate: coastal areas have smaller temperature ranges (less than 25 Celcius degrees because winters are mild, summers are cool and mild), moderate temperatures and more than 1000mm of precipitation per year. More precipitation comes in the winter months. Continental Climate: inland areas are a long way from the moderating effects of the ocean. They have large temperature ranges (more than 25 Celcius Degrees), extreme temperatures (very cold in winter, very hot in summer) and less than 1000mm of precipitation per year. More precipitation comes in the summer months. Pressure Systems and Winds Air Masses: Are volumes of air with similar moisture content and similar temperatures. At any one level above the ground, the air mass will have the same temperature CGC 1D We live in a World of Systems Continental Maritime Polar Maritime Maritime Air Mass Continental Tropical Maritime Conditions Temperature Continental Arctic cold & dry Maritime Polar cold & humid 4C Continental Tropical warm & humid 24C Maritime Tropical cool & humid 24C Air masses carry the characteristics of where they are formed: o Over land – dryer o Over water - moist o Over equator – warm o Over arctic – cold Different air masses don’t mix, where they meet is called a front. Cold air is heavy and dense, and so when it meets warm air, it pushes it up (See cyclonic or frontal precipitation diagram) Land heats up, warm air rises, forms clouds and precipitation (short, strong storms over small area – thunder storms) – Convectional precipitation Warm air moving into cold area causes a warm front. Cold air moving into an area of warm air causes a cold front. o Cloud cover and rain over a larger area o Usually Lighter rain when you have Frontal / Cyclonic precipitation -40C CGC 1D We live in a World of Systems Very Large, General Air Movements in the Lower Atmosphere: Rising Air: This causes unstable conditions Causes a Low Pressure System Results in cloudy weather, rain or snow Descending Air: Air going towards surface (descending) , creates a High Pressure System Results in stable weather, clear, sunny skies Winds: The prevailing winds for most of Canada are called the westerlies because they come from the west. Fact: Winds will blow out of a high pressure area and blow into a low pressure area. H L The Polar Jet Stream This is a very high altitude, very fast wind (300 to 500 km/h, 8000m to 14000m high) It flows west to east. It separates cold arctic air masses from the warmer, southern masses The Jet Stream is further south in winter, allowing cold air to go south into the U.S. The opposite happens in summer. If your location is directly under the Jet Stream you will have unsettled weather CGC 1D We live in a World of Systems Air Masses of North America (see page 81 in Textbook) Winter Air Masses: Which air mass affects Ottawa the most in January? Continental Arctic (N and NW winds from the arctic) Summer Air Masses: Which air mass affects Ottawa the most in July? Atlantic Maritime Tropical (SW winds from the USA) Location of Polar Jet Stream: Where is the Polar Jet Stream in relation to Ottawa in the winter? It is too the south of us going over the middle of the USA. Where is the Polar Jet Stream in relation to Ottawa in the Summer? It is to the north of Ottawa over northern Ontario. Temperature (very cold, cold, warm) Tropical: warm Polar: cold Arctic: very cold Name of Air Mass Moisture Content (wet or dry) Maritime: wet Continental: dry Originates from? Characteristics (moisture & temperature)