Tropics

Question 1

When is Australia’s wet season?

Answer 1

October to April.

Question 2

When is Australia’s dry season?

Answer 2

May to September

Question 3

In which season does most hazardous aviation weather in the tropics occur?

Answer 3

Wet

Question 4

When is Australia’s tropical cyclone season?

Answer 4

November to April

Question 5

What are the ingredients for cyclone formation?

Answer 5

1) warm sea-surface temps greater than 27°C
2) deep moisture at low levels
3) light winds throughout troposphere
4) need convergence as a trigger

Question 6

Between which latitudes doe the ITCZ typically form?

Answer 6

5-20 degrees

Question 7

True or false. The tropics generally oppose the movement of Hadley cells.

Answer 7

False. The tropics generally follow the movement of Hadley cells.

Question 8

What are tropical cyclones?

Answer 8

• Intense depressions forming over tropical oceans with surface temps > 27°C
• Starts as a tropical disturbances and require Coriolis force to develop balanced circular flow

Question 9

How long do tropical cyclones typically last

Answer 9

Last on average 6 days.

Question 10

What are the stages of formation of a cyclone?

Answer 10

• Formative stage
• Immature stage
• Mature stage
• Decaying stage

Question 11

Elements of a cyclone’s formative stage?

Answer 11

• Convergence causes a deepening of pressure towards 1,000 hPa
• Winds reach gale force (34 knots or more) in one quadrant
• Eye forms

Question 12

Elements of a cyclone’s immature stage?

Answer 12

• Central pressure below 1,000 hPa and continues to fall
• Winds reach hurricane force (64 knots or more)
• Spiral bands start forming

Question 13

Elements of a cyclone’s maturing stage

Answer 13

• Central pressure very low and steady’s, 950 hPa in eye
• Bad weather extend to approx. 150 NM from centre
• Strongest winds in left forward quadrant
• Eye: clear sky and light winds

Question 14

Elements of a cyclone’s decaying stage?

Answer 14

• Cyclone moves into area where energy supply is interrupted either by moving over land or if sea temperature decreases.
• Becomes sub-tropical depression of considerable intensity when moving inland or proceeding to higher latitudes.
  —– Winds decrease in strength
  —– Wide-spread flood-rains may continue

Question 15

True or False. During the wet season the ITCZ moves south to latitudes over northern Australia

Answer 15

True