Global Climate Patterns

Question 1

How is Moisture held in the air?

Answer 1

• Air rising at the Equator is hot so it evaporates moisture from the oceans (remember, hot air can also hold more moisture)
  • As it rises, it cools (adiabatically)
  • What happens to air’s ability to hold water when it cools?
  • It decreases – reaches it dew point and rain falls

Question 2

What is the Intertropical Convergence Zone (ITCZ)?

Answer 2

Places around the equator where their is massive amounts of rainfall and these systems are usually associated with very low pressure (equatorial lows ) (<1000 hPa) – ‘depressions’

Question 3

What happens to the air’s moisture as it travels away from the ITCZ and reaches the end of the Hadley Cell?

Answer 3

• It loses its moisture, sinks back down, becomes warmer, and has high pressure – all result in dry air

Question 4

Fill in the labels in the ‘Climate patterns and the main cells’ diagram

Answer 4

https://docs.google.com/document/d/11SlS_6djE3BGAezT2-FeVRTdxG1P1jVyj-u3X2L5qDo/edit?usp=sharing

Question 5

Which Climate cells is Australia part of?

Answer 5

• Australia lies within 2 climate cells
  • Most of it (70%) sits within a Hadley Cell
  • The bottom half is in a Ferrel Cell

Question 6

What are the main wind

directions in Australia’s Climate cells?

Answer 6

Hadley Cell:
- Coming from the south-east
- Easterly direction because it is coming from the pacific
Ferrel Cell:
- Traveling to the south east 
- Coming from the South-West

Question 7

What are the main land masses in Australia to cause air uplift and rain?

Answer 7

• Australia doesn’t have massive mountains and air is generally free to move over the whole continent
• But, the Great Dividing Range does force out most of the moisture from the trade winds
• In the west and south, any moisture is coming from Ferrel westerlies when they hit land

Question 8

How does the tilt of the Earth during different seasons affect the positioning of the Climate Cells over Australia?

Answer 8

• In summer, even more of Australia is in a Hadley Cell as the Earth tilts up
• In winter, the proportion of Australia in a Hadley Cell reduces as the Earth tilts down

Question 9

Due to the tilt of the Earth in summer, what happens to the climate?

Answer 9

• The ‘high’ between the Hadley and Ferrel Cells is at a low latitude
• The east coast gets most of its rain as Hadley Trade Winds dominate the continent
• Not much Ferrel wind contact, so less rain in south and west

Question 10

Due to the tilt of the Earth in winter, what happens to the climate?

Answer 10

• The ‘high’ between the Hadley and Ferrel Cells is at a higher latitude
• We get stable dry highs over most of the north of the continent
  • The south and west get wet Ferrel winds

Question 11

How do the seasons effect the Climate cells and the Equator?

Answer 11

• As the Earth tilts during the seasons, the effective position of the Equator also changes.
• Consequently, the Intertropical Convergence Zone is a band that extends from about 5 Degrees south and north of the Equator, to encompass these shifts

Question 12

Why is rain fall in the tropics of Australia not high during winter?

Answer 12

• In Australia’s winter, northern hemisphere tropical zones are on the effective Equator and so rainfall in the tropics is generally not high.

Question 13

Why is rain fall in the tropics of Australia higher during summer?

Answer 13

• In Australia’s summer, southern hemisphere tropical zones are on the effective equator and this is when most rainfall occurs in these areas, like Cairns and Darwin.

Question 14

What effect does the Climate Cells have on ocean currents?

Answer 14

• The Trade Winds not only affect air flow, they also drive ocean currents
• They blow warm water from the surface of the ocean from east to west
• The displacement of warm water in the east creates a vacuum -> which is filled by underlying denser colder water
• As a result we get convection currents – just like in the atmosphere

Question 15

Fill in the ‘Effect of Trade Winds on The Ocean Currents’ Diagram

Answer 15

https://docs.google.com/document/d/11SlS_6djE3BGAezT2-FeVRTdxG1P1jVyj-u3X2L5qDo/edit?usp=sharing

Question 16

What effect does the Climate Cells have on the temperature of ocean currents?

Answer 16

Based on the Climate cell process, the east coasts of continents in the Southern Hemisphere generally receive warm ocean currents, while the west coasts generally receive cold ocean currents

Question 17

What is El Niño?

Answer 17

• El Niño is a climate cycle in the Pacific Ocean with a global impact on weather patterns.
• It is a disruption to the usual currents due to weakening of trade winds

Question 18

What Climates does Australia have based on the Latitudinal Climate Classification System?

Answer 18

• Temperate: 35 -55 Degrees South
• Sub-Tropical: 20-35 Degrees South
• Tropical: 5 - 20 Degrees South

Question 19

Based on the Latitudinal Climate Classification System, where are the Polar and Equatorial climates?

Answer 19

• Polar: 55 - 90 Degrees South
• Equatorial: 10 Degrees North - 5 Degrees South
• (These change depending on what Hemisphere you’re in)

Question 20

What is Köppen’s system of classification?

Answer 20

• It is essentially a hierarchical system developed by Vladimir P. Köppen, in which three letters are used to classify climate according to
  1. latitudinal zone;
  2. rainfall;
  3. temperature.