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Grade 12 Geography, Climate and weather

In terms of air movement, what is convergence and divergence?

Grade 12 Geography, Climate and weather

Divergence is the movement of air away from an area of high pressure. Convergence is the movement of air towards an area of low pressure.

Grade 12 Geography, Climate and weather

What is the Coriolis force?

Grade 12 Geography, Climate and weather

The Coriolis force deflects moving air as a result of the rotation of the earth.

Grade 12 Geography, Climate and weather

What does ITCZ stand for and what does the acronym refer to?

Grade 12 Geography, Climate and weather

ITCZ stands for Inter-Tropical Convergence Zone. The ITCZ is the meeting place of the tropical easterly winds from each hemisphere.

Grade 12 Geography, Climate and weather

Where is the polar front?

Grade 12 Geography, Climate and weather

The polar front is the boundary between the warm light westerly air mass and the cold dense polar easterly air mass.

Grade 12 Geography, Climate and weather

How do we calculate the pressure gradient of air pressure?

Grade 12 Geography, Climate and weather

The pressure gradient is the horizontal difference in atmospheric pressure.

Grade 12 Geography, Climate and weather

What are tertiary winds?

Grade 12 Geography, Climate and weather

Tertiary winds are local winds that blow over short distances and for short periods of time.

Grade 12 Geography, Climate and weather

In any given area, what is the thermal belt?

Grade 12 Geography, Climate and weather

The thermal belt of an area is the zone of the hottest temperatures, which coincides with the overhead rays of the sun.

Grade 12 Geography, Climate and weather

Explain the term vorticity.

Grade 12 Geography, Climate and weather

Vorticity is the circulation of air around a low pressure centre.

Grade 12 Geography, Climate and weather

Where is the doldrums?

Grade 12 Geography, Climate and weather

The doldrums is a zone of low pressure at the equator.

Grade 12 Geography, Climate and weather

In a valley, what is the angle of incidence?

Grade 12 Geography, Climate and weather

The angle of incidence is the angle at which the rays of the sun strike a slope.

Grade 12 Geography, Climate and weather

Define a cyclone.

Grade 12 Geography, Climate and weather

A cyclone is a low-pressure cell. Cyclones are also called depressions.

Grade 12 Geography, Climate and weather

Describe the movement of air within a tropical cyclone (low pressure system).

Grade 12 Geography, Climate and weather

The pressure is very low In the eye of a tropical cyclone. Air converges and moves upwards in the eye. The rising air rotates around the low pressure system in a clockwise direction in the southern hemisphere and in an anti-clockwise direction in the northern hemisphere.

Grade 12 Geography, Climate and weather

In what direction does air move in an anticyclone?

Grade 12 Geography, Climate and weather

In an anticyclone (high-pressure cell), air moves in an anti-clockwise direction.

Grade 12 Geography, Climate and weather

What is a temperature inversion and what causes it?

Grade 12 Geography, Climate and weather

Temperature inversion occurs when the temperature increases as the altitude increases. Temperature inversions are caused by cold air collecting at the bottom of a valley.

Grade 12 Geography, Climate and weather

Where is the thermal equator?

Grade 12 Geography, Climate and weather

The thermal equator is the zone of greatest heat. It is north or south of the equator depending on the overhead position of the sun.

Grade 12 Geography, Climate and weather

State Ferrel's law.

Grade 12 Geography, Climate and weather

Ferrel's law states that winds are deflected to their left in the southern hemisphere and to their right in the northern hemisphere.

Grade 12 Geography, Climate and weather

Valley climates are influenced by three natural factors: aspect (the direction in which the slope faces), tertiary winds (local winds) and temperature inversions (caused by the cold air collected at the bottom of the valley).

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