Transcript File
Weather and Climate Weather: The day to day characteristics of atmospheric conditions over a short period of time, in a local area. Otherwise, what you get. Factors meteorologist use to determine the Weather: Air temperature Air pressure (decreases with elevation) Wind (moving air) Humidity (moisture in air) Precipitation (rain, snow, hail, etc…) Cloud Cover Use this information to describe today’s weather Factors that Affect Climate Climate: The pattern of atmospheric conditions that takes place over a large area and over a long period of time. Otherwise, what you expect. Factors: Jet Stream Bodies of Water Latitude Ocean Currents Wind and Air Pressure Elevation Relief Jet Stream • In Canada and the United States the wind travels from west to east. • Boundary between the cold dry polar air and warm moist tropical air is called the jet stream • Where this boundary air meets often causes storms Bodies of Water • Water changes temperature much slower than land. • In the summer, water acts as an air conditioner to keep temperatures cool. • In the winter, water acts as a heater to keep temperatures warm. • Therefore, water acts as a moderator. Latitude • As distance from the equator (latitude) increases, the suns rays travel farther and hit the earth surface at an angle which spreads the suns energy over a greater area. • Therefore, polar regions are much cooler than tropical equatorial regions. Ocean Currents • Warm currents heat the air above causing a milder wetter climate • Cold currents cool the air above causing cold dry climates, due to the fact that cold air cannot evaporate as much water as warm air. • Wind blows over ocean currents on to land • Therefore, the warm Alaskan current causes warm wet climate and the cold Labrador current causes cool dry climate. Wind and Air Pressure • The weight of air is called pressure • Wind is caused by the differences in pressure • Warm less dense air rises, cool more dense air falls • Therefore, the greater the differences in pressure, the stronger the wind blows. Elevation • As altitude increases, the corresponding temperature of air decreases. • As warm air rises, its temperature cools causing condensation (clouds). • Therefore, that’s why you get snow on the top of mountains. Relief • Mountains form a natural barrier that causes air masses to rise. • As air is forced to rise it expands, it becomes less dense and cools, leading to condensation • Therefore, very wet on the windward side of mountains and dry on the leeward side.