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Study Jams: Wind and Air Pressure. What causes wind? What are some of the different global wind belts? How does wind affect climate?. Moving Air. Wind. Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure.
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Study Jams: Wind and Air Pressure • What causes wind? • What are some of the different global wind belts? • How does wind affect climate?
Wind • Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure. • Wind is caused from the unequal heating of the earth
Which type of heat transfer causes wind? • Radiation: Sun’s radiation will hit earth at different angles (directly/90 degrees or indirectly/30 degrees) • Convection: Warm air rises, cold air sinks; this causes the air to move • Conduction: Land loses and gains heat quickly, water loses and gains heat slowly. This affects land/sea breezes
Local Winds • Sea breezes and land breezes are local winds that travel short distances and are caused by the unequal heating of land and water (land heats up and cools down faster)
Sea-Breezes • During the day, the land heats up faster than water. The warm air above the land rises, and the cooler air from above the sea moves towards the land, causing a breeze from the sea
Land Breeze • At night, water cools down much slower than the land. The warm air over the ocean rises, and the cooler air above the land moves in towards the sea, causing a breeze from the land
Sea Breeze & Land Breeze Flow Maps • Create a flow-map with pictures that describes how a sea-breeze forms • Create a flow-map with pictures that describes how a land breeze forms
The Sun • The most important source of energy for the Earth
Heating the Earth • The sun heats air, land & water BUT air, water, and land get heated differently. • The sun heats all areas of the Earth BUT different areas of the world get heated differently
So whose getting the most Sun? • Areas around the equator get more sun than areas near the North and South Pole • Small degrees of latitude (0 – 30 degrees) get more sun
GLOBAL WINDS • Global winds are created by the unequal heating of Earth’s surface. • Areas near the equator are heated more, areas near the poles are heated less
Global Winds Global winds divide the Northern Hemisphere into 3 slices and the Southern Hemisphere into 3 slices. The slices are mirror images of each other (just like lines of latitude!) 3 2 1 1 2 3 1 = tradewinds 2 = westerlies 3 = polar easterlies
GLOBAL WINDS • Global winds are an example of CONVECTION because heat is circulated around the globe by the movement of a fluid (AIR!).
Global Winds • The combination of pressure belts and the Coriolis Effect cause global winds • Brainpop! 1:14 – 2:26 • http://www.brainpop.com/science/weather/wind/
Coriolis Effect Earth’s rotation causes wind to blow in a curved path (clockwise in Northern hemisphere, and counterclockwise in Southern hemisphere) If the Earth did not move, winds and currents would blow and flow in straight line.
GLOBAL WIND BELTS Global winds are named based off of where they COME FROM!
Polar Easterlies • Polar Easterlies: Wind belts that extend from the poles to 60° latitude • Formed from cold sinking air moving from the poles creating cold temperatures
Westerlies • Westerlies: Wind belts found between 30° and 60° latitude • Flow towards the poles from west to east carrying moist air over the Unites States
Trade Winds • Trade Winds: Winds that blow from 30° almost to the equator • Called the trade winds because of their use by early sailors
Doldrums • Doldrums: Located along the equator where no winds blow because the warm rising air creates and area of low pressure
Horse Latitudes • Horse Latitudes: Occur at about 30° north and south of the equator where the winds are very weak • Most deserts on the Earth are located here because of the dry air
Jet Stream • The jet streams are narrow belts of high speed winds that blow in the upper troposphere and lower stratosphere • Separates warm air from cold air
GLOBAL WINDS • Global winds are an example of CONVECTION because heat is circulated around the globe by the movement of a fluid (AIR!).
Wind: Review Questions On a sheet of paper, answer the following questions with a partner. Write in complete sentences (restate question( • What causes winds to blow? • Describe the differences between hot and cold air (density, pressure, direction it flows) • Why do winds not flow in a straight line from the poles to the equator? (why do we have three separate wind belts in each equator) • What are the two calm regions of very high or low pressure where winds do not blow very much?
Independent Practice Wind Reading Belts & Land and Water Breezes worksheet • Complete for homework