Tropical Cyclones

Question 1

What conditions are needed for Tropical cyclones to form?

Answer 1

-Tropical oceans (temperatures 27C and above) and depths of 60 to 70m (this prevents cool water rising via stirring of the water and killing the system). -The Coriolis Force must be felt to cause the revolving nature of the storm (they occur between 5-20’ on both the NH and SH). -Wind speed must not change with height -“Barotropic” atmospheric conditions -Divergence in the upper atmosphere -Pre-existing low level disturbance

Question 2

What does barotropic mean?

Answer 2

Uniform heat, pressure and humidity

Question 3

Draw the structure of a tropical cyclone

Answer 3

Question 4

Describe the structure and movement of a tropical cyclone

Answer 4

• Outer connective band around edge of main cloudmass. It is fragmented at a point of local instability.
• The main cloudmass creates overcast. Pressure drops on approach to the eye. Winds reach 150-180mph
• Everything is at its most intense at the eyewall except rain which cannot overpower extreme updrafts.
• The eye is the centre of the storm and is usually 20-50km in diameter. Winds decrease to 8mph in 20 minutes.
• Rainfall stops, temperature rises an the sun becomes visible.