Lecture: Global Atmospheric Circulation Model

Objectives

• Explain the global atmospheric circulation model.
• Explain how circulation cells transfer heat energy around the world.

Key Concepts

The Sun as a Heat Source

• The Sun provides heat to Earth, causing water to change from liquid to vapor (evaporation).
• Rising warm air contains water vapor.

The Equator

• Imaginary line around the Earth's center.
• Receives a larger share of the Sun's rays, leading to large amounts of rising moist air.
• Low pressure area due to rising warm, wet air.

Atmospheric Circulation

• Air rises, spreads out at the top of the atmosphere, cools, and water vapor condenses, forming clouds.
• Precipitation occurs (rain, sleet, snow).

Pressure Areas

• Low Pressure Areas: Common precipitation, wet climates, high rainfall.
• High Pressure Areas: Less precipitation, arid (dry) climates.

Circulation Cells

• Hadley Cell:
  • Moves warm air from the Equator (0°) to 30° north and south.
  • Moves cool air from 30° back to the Equator.
• Ferrel Cell:
  • Moves warm air from 60° to 30° north and south.
  • Moves cool air from 30° to 60°.
• Polar Cell:
  • Moves slightly warm air from 60° to the poles (90°).
  • Moves cold air from 90° back to 60°.

Pressure Bands

• 0° (Equator): Low pressure band.
• 30°: High pressure band.
• 60°: Low pressure band.
• 90° (Poles): High pressure band.

Summary

• Understanding the function of atmospheric circulation cells in transferring heat energy globally.

Additional Resources

• Workbooks and test papers related to this topic are available at backroadtutoring.com.