Lecture: Global Wind Patterns and Atmospheric Circulation
Key Concepts
- Atmospheric Circulation: Refers to the large-scale movement of air, which helps distribute thermal energy (heat) across the surface of the Earth.
- Global Wind Patterns: These are created by the uneven heating of the Earth’s surface and are influenced by the rotation of the Earth.
Main Atmospheric Cells
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Hadley Cell:
- Located between the equator and 30° latitude.
- Warm air rises at the equator, creating low pressure.
- The air cools and sinks at around 30° latitude, creating high pressure.
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Ferrel Cell:
- Located between 30° and 60° latitude.
- Air moves poleward and eastward near the surface and equatorward and westward at higher altitudes.
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Polar Cell:
- Extends from 60° latitude to the poles.
- Air at the poles is cold and dense, causing it to sink.
- This air flows toward lower latitudes and rises around 60° latitude.
Trade Winds
- Originate from the subtropical high-pressure belt and blow towards the low-pressure regions at the equator.
- East-to-west direction in both hemispheres.
Westerlies
- Winds blowing from the west to the east in the mid-latitudes between 30° and 60°.
- Plays a crucial role in influencing weather patterns.
Polar Easterlies
- Cold, dry prevailing winds that blow from the east to the west between 60° latitude and the poles.
The Coriolis Effect
- Describes how the rotation of the Earth affects the direction of winds and ocean currents.
- Causes moving air and water to turn and twist instead of moving in a straight line.
ITCZ (Intertropical Convergence Zone)
- Area encircling the Earth near the equator where the northeast and southeast trade winds converge.
- Characterized by convective activity which often results in thunderstorms and heavy rains.
Practical Implications
- Understanding wind patterns is crucial for navigation, aviation, and predicting weather.
- Influences climate by distributing heat and moisture around the Earth.
These notes provide a summary of key points related to global wind patterns and atmospheric circulation, suitable for study and review.