Storms - Lecture 6

Question 1

How do cyclones form?

Answer 1

Collection of thunderstorms - warm, moist air
Energy through heat and latent heat released
Rising of parcel of air, pressure drops, cool and condensation - energy released
Sucks in more air below (positive feedback)

Question 2

What is latent heat?

Answer 2

Warm ocean evaporates with altitude (liquid -> gas) Energy is released upon condensation gas -> liquid

Question 3

How are tropical storms formed?

Answer 3

Build up of heat in summer, thunderstorms draw in air and create area of LP (equatorial regions) - more updraft, more suction

Question 4

Cyclone direction in relation to earth’s rotation and N hemisphere

Answer 4

Always spin in same direction due to earth’s rotation
Pressure gradients H-L
N-hemisphere deflected to right

Question 5

Why do cyclones spin? Include equation

Answer 5

A conserved quantity of angular momentum - remains constant unless acted upon by external
L=rmv
Radius and velocity are related - if smaller radius, velocity increases
Strong circulation + conservation of angular momentum = air spins faster (vortex and wind) and air descends through eye

Question 6

What does L=rmv stand for?

Answer 6

L (angular momentum) = r (radius) m (mass) v (rotational velocity

Question 7

What are storm surges and how are they formed?

Answer 7

LP under storm - elevated water surface
Wind drag pushes onshore - hill of water
Lower bed slope, more piling
Surge higher in shallower waters

Question 8

Effects of storm surges?

Answer 8

Flooding with a current
Destructive
Can cut inlets
Morphology rearranged 
Waves dissipate quickly