Wind

Question 1

Coriolis force

Answer 1

Rotation of earth acts perpendicular to direction of wind motion
Southern hemisphere backs (anti clockwise)
Only effects direction not speed
Faster wind means more coriolis
CF maximum at poles 0 at equator

Question 2

Pressure gradient

Answer 2

Wind high p to low p

Question 3

Friction layer

Answer 3

SFC-2000’
Slows down flow of wind due to drag
Therefore decreases CF
Southern hemisphere high p flows anti clockwise
Low p flows clockwise
Depth determined by density speed and surface roughness
Sea less friction land more friction

Question 4

Friction layer wind speed

Answer 4

Rule of thumb 2/3 2000’ wind
Gusting mean 2000’ wind
Veered 30° from 2000’

Question 5

Geostrophic wind

Answer 5

Balanced by CF and PGF
Flows parallel to isobars

Question 6

Buys ballots law

Answer 6

In northern hemisphere back to geostrophic wind low pressure will be on your right

Question 7

Diurnal variation land

Answer 7

Day : land heats
Friction layer deepens
Faster air aloft mixes to surface
Surface wind increases and backs

Night:
Land cools surface wind stays low
Weaker and calm wind
Slower speed less CF wind perpendicular to geostrophic

Southern hemisphere backs and increases after sunrise and veers and decreases after sunset

Question 8

Diurnal variation over sea

Answer 8

Minimal difference due to high specific heat of ocean

Question 9

Squall

Answer 9

Sudden increase in wind speed associated with CB showered, TS, +shra

Question 10

Gust lull

Answer 10

Over 10kts reported

Question 11

Wind socks ° indications

Answer 11

30° 8kts
45° 15 kts
75° 22kts
90° 25+kts

Question 12

Wind shear

Answer 12

Significant difference in wind speeds between layers of air