Atmospheric Circulation Model

Question 1

What are the 3 circulation cells?

Answer 1

Hadley, Ferrel and Polar

Question 2

Which cell is closest to the Equator?

Answer 2

The Hadley cell.

Question 3

What are the features of the Hadley cell?

Answer 3

Hadley cell:
*Stretches from the Equator to latitudes 30 N and 30 S.
*Warm trade winds blow towards the Equator.
*The warm air rises rapidly causing thunderstorms.
*An area of low pressure is formed in the ITCZ where the air from the two cells meet over the Equator.
*Air at the top of the troposphere moves towards 30 N and 30 S where it becomes cooler and starts to sink back to the Earth’s surface.
* This creates high pressure and you find the world’s
hottest deserts in these areas.

Question 4

What are the features of the Ferrel cell?

Answer 4

Ferrel cell:

• Stretches from latitudes 30 N and 30 S to 60 N and 60 S.
• Air on the surface is pulled towards the poles. This forms the warm southwesterly winds in the northern hemisphere and northwesterly winds in the southern hemisphere.
• These winds collect moisture as they blow over oceans on the Earth’s surface.
• At about 60 N and 60 S they meet cold air at the poles.
• The warm air rises over the cold air as it is less dense. This produces low pressure at the Earth’s surface and pressure systems known as depressions.
• Some of the air returns to the tropics and some diverted to the poles as part of the Polar cells.
• The cell has a motion to the right in the northern hemisphere and to the left in the southern hemisphere due to the spin of the Earth. This is known as the Coriolis effect.

Question 5

What are the features of the Polar cells?

Answer 5

Polar cells:

• Stretches from latitudes 60 N and 60 S to the north and south poles.
• The air sinks over the poles producing high pressure.
• The air then flows towards the low pressure in the mid-latitudes, about 60 N and 60 S. Here it meets the warm air of the Ferrel cells.

Question 6

Definition of Global Atmospheric Circulation

Answer 6

The worldwide movement of air which transport heat from tropical to polar latitudes.

Question 7

Definition of Latitude

Answer 7

The distance north or south of the equator. It is measured in degrees the maximum being 90 N or 90 S.

Question 8

Definition of Hemisphere

Answer 8

A half of the Earth. The northern hemisphere is above the Equator and the southern hemisphere is below the Equator.

Question 9

Definition of Troposphere

Answer 9

The lowest layer of the atmosphere. It is thicker at the Equator (approx. 20 km) that at the poles (approx. 10 km).

Question 10

Definition of Depression

Answer 10

A low-pressure system that produces cloud, wind and rain.

Question 11

Definition of Ocean Current

Answer 11

A continuous, directed movement of ocean water. The currents are made from forces acting on the water such as the wind, different temperature and the Earth’s rotation.

Question 12

Definition of Trade Winds

Answer 12

A wind that blows steadily from the tropics towards the Equator. In the northern hemisphere it is from the northeast and in the southern hemisphere from the southeast.

Question 13

What does ITCZ stand for?

Answer 13

Inter Tropical Convergence Zone

Question 14

What are the features of Global Atmospheric Circulation?

Answer 14

• The transfer of heat from the Equator to the poles.
• 3 circulation cells (Hadley, Ferrel, Polar)
• Jet streams impact on the movement of heat energy.
• The spin of the Earth creates the Coriolis effect.