Global Wind Patterns
Name: ________________________________________ Period: ____ Date: _______
Essential Question: How do I describe the global wind patterns?
The region of Earth receiving the Sun's direct rays is the equator. Here, air is heated and rises,
leaving low pressure areas behind. Moving to about thirty degrees north and south of the equator, the
warm air from the equator begins to cool and sink. Between thirty degrees latitude and the equator,
most of the cooling sinking air moves back to the equator. The rest of the air flows toward the poles.
The air movements toward the equator are called trade winds- warm, steady breezes that blow almost
continuously. The Coriolis Effect makes the trade winds appear to be curving to the west, whether they
are traveling to the equator from the south or north. The Coriolis effect is the apparent curvature of
global winds, ocean currents, and everything else that moves freely across the Earth’s surface. The
curvature is due to the rotation of the Earth on its axis. The effect was discovered by the nineteenth
century French engineer Gaspard C. Coriolis.
The trade winds coming from the south and the north meet near the equator called the
Intertropical Convergence Zone or ITCZ. These converging trade winds produce general upward winds
as they are heated, so there are no steady surface winds. This area of calmness and almost windless is
called the doldrums. Sailors in the early years used to get stranded in this region.
Between thirty and sixty degrees latitude, the winds that move toward the poles appear to
curve to the east. Because winds are named from the direction in which they originate, these winds are
called prevailing westerlies. Prevailing westerlies in the Northern Hemisphere are responsible for many
of the weather movements across the United States and Canada.
At about sixty degrees latitude in both hemispheres, the prevailing westerlies join with polar
easterlies to reduce upward motion. The polar easterlies form when the atmosphere over the poles
cools. This cool air then sinks and spreads over the surface. As the air flows away from the poles, it is
turned to the west by the Coriolis effect. Again, because these winds begin in the east, they are called
easterlies.
Clarifying Questions:
1. What region of Earth receives direct sunlight?
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2. Describe the air in the equator?
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3. What are Trade winds?
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4. How are Trade winds affected by the Coriolis effect?
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5. What causes the Coriolis Effect?
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6. Where do the Northeast and Southeast Trade winds meet?
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7. Describe doldrums.
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8. Why did the early sailors get stranded in doldrums region? Think!
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9. Why do the winds curve to the East between 30-60 degrees? Think! Clue: Earth rotates on its axis.
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10. What is the direction of the winds between 30-60 degrees? Remember: Wind is described where it
comes from. __________________________________________________________________________
11. What type of global wind is mainly responsible for the weather in the United States and Canada?
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11. Describe the Polar easterlies.
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12. How are the Polar easterlies affected by the Coriolis Effect?
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13. Why are Polar Global winds called Polar Easterlies? Think!
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14. Describe the movement of air from the equator and poles. ( Use the chart)
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15. Describe Hadley cells. ( Use the chart) Observe and think!
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16. Why is the wind on Earth not blowing straight? Think!
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17. Identify the type of Global wind. ( Trade Winds, Prevailing Westerlies, Polar Easterlies)
a. 0-30 degrees _______________________________________
b. 30-60 degrees ______________________________________
c. 60-90 degrees ______________________________________
http://kids.earth.nasa.gov/archive/nino/global.html
Youtube:
https://www.youtube.com/watch?v=lrPS2HiYVp8
Coriolis effect: https://www.youtube.com/watch?v=i2mec3vgeaI
Jet Stream: https://www.youtube.com/watch?v=GvXPtQuQtiU