Global Circulation

Question 1

Equatorial Trough
What is it
Where is it
Weather

Answer 1

• Belt of low pressure near equator (high radiation)
• Converging airstreams rise over warm water (air is moist)
• Air rises, cools & expands = extensive cloud
• Cloudy region w frequent rain

Question 2

Sub-Tropical Ridge
What is it
Where is it
Weather

Answer 2

• Belt of high pressure between low pressure areas on Earth
• Relatively free of cloud

Question 3

Polar Front
What is it
Where is it
Weather

Answer 3

• Low pressure region
• Separates cold polar air & warm sub-tropic air
• Waves of cold polar air brake free from polar cell & track N -> producing cold fronts

Question 4

Polar High
What is it
Where is it
Weather

Answer 4

• Sinking cold air over poles
• Permanent high pressure region

Question 5

How does global circulation help the earth ?

Answer 5

Air regulates earths temp

Redistributes sun heat evenly

Question 6

What is the air regions that Australia’s in

Answer 6

Tropical zone (North)
&
Sub-tropical zone (South)

Question 7

How does global circulation work

Answer 7

1 ) Sun heats Earth

2 ) Air in contact with surface warms & rises - (if air in contact w water vapour - condenses & forms cloud)

3 ) At troposphere air stops rising -> cools & sinks

• Tropical Cell = Cool air sinking in hot religion = heats up & rises -> convective cell
• Polar Cell = Cool air sinking at the poles = air moves away into warmer region & becomes warn enough to rise & flows back to poles & sinks -> convective cell

Question 8

High Pressure
Movement & Weather

Answer 8

• Anticlockwise (Southern hemisphere)
• Flying towards High pressure system = winds from left
• Sinking air
• Stable air
• Cloud free

Question 9

Low Pressure
Movement & Weather

Answer 9

• Clockwise (Southern hemisphere)

Flying towards Low pressure system = winds from right

• Rising air
• Expands & cools
  (Carries water vapour up with it -> reaches dew point temp & condenses to form cloud)”
• Cloudy & rainy

Question 10

What does Atmospheric pressure depend on ?

Answer 10

• The crowding of molecules into a given volume
• crowding of molecules depends on the weight of air above compressing the surface air

Question 11

Are winds travelling from the Equator to the poles weaker or stronger ?

Answer 11

Stronger

• Equator is a wider region
  Winds go to a smaller region (in diameter) -
• Smaller region moving slower (has not caught up)
• Imagine skater spinning -> when leg is out spinning = slower -> polls leg in spinning = Faster

Question 12

Winds going from the Poles to the Equator
How do they act ?

Answer 12

• Wind goes to the right left of its target
• Equator moving faster then Poles
  (Equator moved ahead of the ball)

Question 13

What is the Polar front

Answer 13

• Boundary between cold polar air & warm tropical air
• Occurs at 11-13 km
• Can be strong temp contrast -> Polar Front jet can be rlly strong (in summer when contrast is high)

Question 14

What forms Trade winds ?

Answer 14

Surface flow of Hadley cells
- Air flow towards equator -> wind flows to the West (in both hemispheres)

Question 15

What is a Jet Stream ?

Answer 15

Fast flowing current of air at high altitudes

Can reach speeds of over 200 mph

Question 16

What are the major Jet Streams

Answer 16

Polar Fronts jets
&
Subtropical jets