Wind

Question 1

Describe the effect of the coriolis force on moving air (20.12.2)

Answer 1

A mass moving in a rotating system experience a force and acts perpendicular to the direction of motion/wind

Question 2

State the horizontal component of the Coriolis force equation

Answer 2

Horizontal CF= 2ΩvsinΦ
•Ω = Earths angular velocity
•Φ = Latitude

Question 3

State the changes in the magnitude of the coriolis force with latitude

Answer 3

Higher latitudes = increased Coriolis force
•Equator = 0° latitude therefore zero horizontal CF
•Strongest at the poles

Question 4

State the relationship between the wind speed and the coriolis force

Answer 4

Proportional to windspeed
•Increase in wind speed = increase of Coriolis force

Question 5

State the direction of the coriolis force relative to the wind direction in the different hemispheres

Answer 5

Deflects left in the SH

Right in NH

Question 6

Define the geostrophic wind in the SH

Answer 6

Exact balance of coriolis force and pressure gradient. Straight parallel isobars and absence of any friction

Question 7

Describe the gradient wind in the SH with respect to anticyclonic isobars

Answer 7

Read book

Question 8

Describe gradient wind in SH with respect

Answer 8

Read book

Question 9

Describe frictional wind balance

Answer 9

Results from how rough the surface is. Rougher the surface greater the friction which acts to slow wind down by opposing the direction of flow.

As wind speed is decreased magnitude of coriolis force decrease meaning PGF dominates over and wind bends to the right.

Because wind changes direction, so the CF must also change direction to remain at right angles to the wind. Since friction always opposes wind direction, friction vector must also change by an equal amount of degrees in a clockwise direction.

Question 10

State the typical wind direction deflections due to friction over the sea, flat to undulating ground and mountainous regions.

Answer 10

Sea
10-20º

Flat
30º

Undulating
40º-60º

Mountain
90º

Question 11

Explain how atmospheric stability changes height of friction layer

Answer 11

Stable = reduced vertical extent

Unstable = increased vertical extent

Question 12

Explain how wind strength affects the depth of the friction layer

Answer 12

Stronger wind = deeper friction layer

Weaker wind = reduced friction layer

Question 13

Explain how surface roughness affects the depth of the friction layer

Answer 13

Rougher surface = deeper friction layer

Smoother surface = reduced friction layer