Global atmospheric circulation

Question 1

What is Global Atmospheric Circulation?

Answer 1

The movement of air across the planet occurs in a specific pattern. The whole system is driven by the equator, which is the hottest part of the Earth. Air rises at the equator, leading to low pressure and rainfall. When the air reaches the edge of the atmosphere, it cannot go any further and so it travels to the north and south. The air becomes colder and denser, and falls, creating high pressure and dry conditions at around 30° north and south of the equator. Large cells of air are created in this way.

Question 2

The Hadley cell

Answer 2

The first cell is called the Hadley cell. At the equator, the ground is intensely heated by the sun. This causes the air to rise which creates a low-pressure zone on the Earth’s surface. As the air rises, it cools and forms thick cumulonimbus (storm) clouds. The air continues to rise up to the upper atmosphere

Question 3

subtropical high-pressure zone.

Answer 3

When it reaches about 30° north and south, the air cools and sinks towards the ground forming the

Question 4

Desserts location

Answer 4

As the air sinks, it becomes warmer and drier. This creates an area of little cloud and low rainfall, where deserts are found.

Question 5

Trade winds

Answer 5

The Hadley cell is then complete. The air completes the cycle and flows back towards the equator.

Question 6

Coriolis force

Answer 6

an effect whereby a mass moving in a rotating system experiences a force (the Coriolis force ) acting perpendicular to the direction of motion and to the axis of rotation.

Question 7

Farrel cell

Answer 7

The Ferrel cell occurs at higher latitudes (between 30 degrees and 60 degrees N and 30 degrees and 60 degrees S):

Question 8

Polar cells

Answer 8

At the poles, air is cooled and sinks towards the ground forming high pressure, this known as the Polar high.