Climate, Atmospheric Circulation

Question 1

Convection

Answer 1

The vertical transport of heat and moisture in the atmosphere. Warm air goes up and condenses into clouds

Question 2

Pressure

Answer 2

The physical force exerted on the Earth’s surface from the atmosphere’s weight

Question 3

What happens to pressure at higher altitudes?

Answer 3

Pressure decreases at higher altitutudes due to the lesser amount of atmosphere to pass through

Question 4

Isobar

Answer 4

Join parts of equal pressure on a map. These pressure gradients are responsible for the movement of air

Question 5

How does heat capacity differ between the land and the ocean, and what are the consequences?

Answer 5

Land has a lower heat capacity than the ocean so temperature increases at a faster rate. Subsequently, low pressure gradients form and go out to sea. Since the ocean has a higher heat capacity than the land, the air sinks, causing high pressure gradients to form and be carried back to land

Question 6

What causes wind?

Answer 6

Wind is caused by spatial differences in atmospheric pressure which arise from the Earth’s uneven absorption of solar radiation

Temperature increases → Air density decreases → Pressure decreases

Question 7

Coriolis Force

Answer 7

Because of the Earth’s rotation, wind (and therefore currents) are deflected from a straight path.

Northern hemisphere: Deflect to the right

Southern hemisphere: Deflect to the left

Question 8

Inter-Tropical Convergence Zone (ITCZ)

Answer 8

A wind band encircling the Equator that has low pressure (forming the Equatorial Trough) and therefore experiences calmer weather.

Question 9

Hadley cell

Answer 9

A convection cell where air rises at the Equator, sinking as it moves poleward

Question 10

Trade winds

Answer 10

The return flow of winds that are deflected due to Coriolis force. Air descends down to the Equator, forming reliable NE and SE trade winds

Question 11

Subtropical high pressure belt

Answer 11

A wind band encircling the subtropics. Forms from the descending branches of Hadley cells, creating large, persistent anticyclones. Due to their persistence, calmer conditions result

Question 12

Doldrums

Answer 12

Belts of low pressure near the Equator where winds from either hemisphere converge and and re-directed due to Coriolis forces

Question 13

Westerlies

Answer 13

Poleward blowing winds in the subtropics

Question 14

Polar Easterlies

Answer 14

Winds from the poles blowing towards the subtropics/Equator

Question 15

How do the Westerlies and Polar Easterlies interact?

Answer 15

When the Westerlies and Polar Easterlies converge, a low pressure trough (polar front) is formed from the vast temperature contrast.

Question 16

What weather feature results from the interaction between Westerlies and Polar Easterlies?

Answer 16

Extratropical cyclone at the boundary of their convergence

Question 17

What causes monsoons?

Answer 17

Monsoons form near the Equator (mostly near Asia) where the land and sea have a high temperature contrast. Coriolis forces causes the winds to be immediately directed back towards land

Question 18

Cyclone

Answer 18

A large wind system that circulates around a centre of low atmopsheric pressure either in a clockwise or anticlockwise direction depending on the hemisphere it forms in. Volatile weather results

Question 19

Anticyclone

Answer 19

A large wind system that circulates around a centre of high atmospheric pressure either in a clockwise or anticlockwise direction depending on the hemisphere it forms in. Calm weather results