What are the causes of the pressure belts

http://www.preservearticles.com/201107149089/brief-note-on-the-formation-of-the-major-pressure-belts.html

The causes of pressure belts can be explained by understanding the principles of atmospheric circulation and the distribution of solar energy on Earth. Here's how you can understand the causes:

1. Unequal Heating: The primary cause of pressure belts is the uneven heating of Earth's surface by sunlight. As sunlight hits the equator more directly, the equatorial regions receive more solar energy than the polar regions.

2. Convection Cells: The uneven heating leads to the formation of convection cells in the atmosphere. Convection is the process by which heat is transferred through the movement of fluid (in this case, air). The two main convection cells are the Hadley cell and the Ferrel cell.

3. Hadley Cell: The Hadley cell is responsible for the formation of the equatorial low-pressure belt. At the equator, the intense heating causes air to rise, creating a low-pressure zone. As the air rises, it cools, loses moisture, and forms clouds, resulting in heavy rainfall in these regions.

4. Trade Winds: The rising air at the equator creates a region of low pressure. To replace this rising air, air from the subtropical high-pressure zones moves towards the equator, resulting in the development of trade winds from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere.

5. Subtropical High-Pressure Zones: The sinking air in the subtropical regions around 30 degrees latitude creates high-pressure zones (the subtropical high-pressure belts). These regions are characterized by clear skies, dry conditions, and descending air.

6. Polar Cells and Polar High-Pressure Belts: At the poles, cold air descends, forming high-pressure zones known as the polar high-pressure belts. These cells connect with the Ferrel cell, completing the atmospheric circulation loop.

Overall, the combination of the Hadley cell, Ferrel cell, and polar cell creates a pattern of alternating high and low-pressure belts, known as the global atmospheric circulation. These pressure belts play a crucial role in shaping weather patterns, winds, and ocean currents around the world.