9th Grade Chapter 2 Lesson 4


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9th Grade Chapter 2 Lesson 4

  1. 1. 9 th Grade: Chapter 2 Lesson 4 Pgs. 39-49 For Student Use Only
  2. 2. Patterns of Circulation <ul><li>Atmosphere </li></ul><ul><ul><li>The atmosphere constantly moves because of the uneven heating of across the surface of the earth. </li></ul></ul><ul><ul><ul><li>Rising Air= low pressure. This is called a LOW pressure region </li></ul></ul></ul><ul><ul><ul><li>Cooling air= high pressure. This is called a HIGH pressure region </li></ul></ul></ul><ul><ul><ul><li>Are always moves from high to low pressure. </li></ul></ul></ul>
  3. 3. Patterns of Circulation <ul><li>Air Currents </li></ul><ul><ul><li>Unequal heating of the earth also causes major air movements from the poles to the equator </li></ul></ul><ul><ul><li>These are GLOBAL CONVECTION CURRENTS! </li></ul></ul>
  4. 4. Patterns of Circulation <ul><li>Global Wind Zones </li></ul>
  5. 5. Patterns of Circulation <ul><li>Winds </li></ul><ul><ul><li>Normally winds would travel North to South, but the Earth spins. </li></ul></ul><ul><ul><li>This spinning is called the CORIOLIS EFFECT. </li></ul></ul><ul><ul><ul><li>Coriolis Effect: The change in course of the winds due to the earth’s rotation. </li></ul></ul></ul><ul><ul><li>Coriolis Effect: Works because of Inertia and Speed. </li></ul></ul>
  6. 6. Patterns of Circulation <ul><li>Winds: </li></ul><ul><ul><li>Coriolis Effect: </li></ul></ul><ul><ul><ul><li>Factors that affect the Coriolis Effect : </li></ul></ul></ul><ul><ul><ul><ul><li>Inertia- an object in motion will stay in motion at a constant speed and direction until an outside force acts upon it. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Speed: Objects at different distances from the axis travel and different speeds. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Closer to the axis slower speeds, farther from the axis faster speeds. </li></ul></ul></ul></ul></ul>
  7. 7. Patterns of Circulation <ul><li>Coriolis Effect: </li></ul><ul><ul><li>The earth’s surface will outrun objects. </li></ul></ul><ul><ul><li>This appears to make them curve in the air. </li></ul></ul><ul><ul><li>The object stays at the same speed and direction, but the earth moves. </li></ul></ul><ul><ul><li>This movement also causes the winds to appear to shift! </li></ul></ul>
  8. 8. Patterns of Circulation <ul><li>Earth’s Movement and Winds: </li></ul><ul><ul><li>Cyclone: circles counterclockwise as the air rushes towards the low pressure area </li></ul></ul><ul><ul><li>Anticyclone: circles clockwise as the air rushes from the high pressure area </li></ul></ul>
  9. 9. Patterns of Circulation <ul><li>Earth’s Global Wind Zones </li></ul><ul><ul><li>Equatorial Zone: (at the Equator) Where warm air rises called the ITCZ (Inter-Tropical Convergence Zone) </li></ul></ul><ul><ul><ul><li>Doldrums: Area of light breezes or no breezes due to the rising motion of the air </li></ul></ul></ul><ul><ul><li>Horse Latitudes: (30 ° North and South) where cooler air sinks, little to no breezes. People used to have to dump their horses. </li></ul></ul>
  10. 10. Patterns of Circulation <ul><li>Earth’s Global Wind Zones </li></ul><ul><ul><li>Trade Winds: These are where the winds blow towards the equator. </li></ul></ul><ul><ul><ul><li>Northern Hemisphere- blow from the Northeast to the Southwest (called the Northeast Trade Winds) </li></ul></ul></ul><ul><ul><ul><li>Southern Hemisphere- blow from the Southeast to the Northwest (called the Southeast Trade Winds) </li></ul></ul></ul>
  11. 11. Patterns of Circulation <ul><li>Earth’s Global Wind Zones </li></ul><ul><ul><li>Polar Easterlies: Winds blow away from poles to the lower latitudes. </li></ul></ul><ul><ul><ul><li>Northern Hemisphere- blow out of the Northeast. </li></ul></ul></ul><ul><ul><ul><li>Southern Hemisphere- blow out of the Southeast </li></ul></ul></ul><ul><ul><li>Prevailing Westerlies: Winds that blow up from the horse latitudes and rush to fill in the warmed polar air. </li></ul></ul><ul><ul><ul><li>Northern Hemisphere- blow out of the Southwest </li></ul></ul></ul><ul><ul><ul><li>Southern Hemisphere- blow out of the Northwest </li></ul></ul></ul><ul><ul><li>Jet Stream: Winds in the upper troposphere that move quickly and meander around </li></ul></ul>
  12. 12. Patterns of Circulation <ul><li>Local Winds: </li></ul><ul><ul><li>Not global- found only in certain areas. </li></ul></ul><ul><ul><ul><li>Monsoons- Seasonal change in wind (winds reverse directions) which causes a dry season and a wet season. Caused by uneven heating of large land and water masses. </li></ul></ul></ul><ul><ul><ul><li>Sea and Land Breezes- Daily switching of wind direction due to uneven heating of land and water. </li></ul></ul></ul><ul><ul><ul><ul><li>Sea Breeze: Cooler air from the sea blows into shore in the afternoon. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Land Breeze- At night the cooler air over the land blows out from the land to the sea. </li></ul></ul></ul></ul>
  13. 13. Patterns of Circulation <ul><li>Local Winds: </li></ul><ul><ul><li>Mountain Breezes: At night cooler air rushes down from the mountain into the warmer valley. </li></ul></ul><ul><ul><li>Valley Breezes: In the day cooler air from the valley rushes into the warmer mountain air. </li></ul></ul>