C10 - Low Level Winds

Question 1

Define Wind?

Answer 1

Sustained horizontal movement of Air.

Question 2

Define Wind Velocity?

Answer 2

Wind Speed and Direction.

Question 3

Wind Direction is given using ‘____’ North and indicates the direction ‘____’ which the Wind blows (2)?

Answer 3

• True.

- From.

Question 4

What is a Westerly Wind?

Answer 4

Wind coming from W/270°.

Question 5

What direction does the Wind change if it is said to be Backing?

Answer 5

Anti-clockwise.

Question 6

What direction does the Wind change if it is said to be Veering?

Answer 6

Clockwise.

Question 7

Approximately 1 mps (metre per second) is equal to what in Knot?

Answer 7

2 kt.

Question 8

A sudden increase in Wind Speed, often with a change in direction, lasting only a few seconds. What am I?

Answer 8

Gust.

Question 9

A sudden increase in Wind Speed, often with a change in direction, lasting for some minutes. What am I?

Answer 9

Squall.

Question 10

A ‘____’ is a sudden decrease in Wind Speed?

Answer 10

Lull.

Question 11

A straight line from a circle shows what on Weather Charts?

Answer 11

Where this wind is blowing to.

Question 12

On a Weather Charts, if the Wind Velocity Line has a feather point out, how much does this represent?

Answer 12

10 kt.

Question 13

On a Weather Charts, if the Wind Velocity Line has a black triangle, how much does this represent?

Answer 13

50 kt.

Question 14

On a Weather Charts, if the Wind Velocity Line has a small feather point out, how much does this represent?

Answer 14

5 kt.

Question 15

On a Weather Charts, if the Wind Velocity Line has a small feather, 2 feather lines and a black triangle, how much does this represent?

Answer 15

75 kt.

Question 16

Surface wind is defined as the Wind Velocity at ‘____’ Above Ground Level?

Answer 16

33 ft.

Question 17

What is the maximum speed of a Wind Sock?

Answer 17

20 kt.

Question 18

The ‘____’ is the force that acts from areas of High-Pressure towards areas of Low-Pressure?

Answer 18

Pressure Gradient Force.

Question 19

Closely spaced Isobars indicate a ‘____’ Pressure Gradient Force and thus ‘____’ (2)?

Answer 19

• Large.

- Strong Winds.

Question 20

Widely spaced Isobars indicate a ‘____’ Pressure Gradient Force and thus ‘____’ (2)?

Answer 20

• Weak.

- Light Wings.

Question 21

‘____’ is an effect caused by the rotation of the Earth?

Answer 21

Coriolis.

Question 22

Coriolis Force acts at ‘____’ to the ‘____’ of the Wind in the Northern Hemisphere (2)?

Answer 22

• 90°.

- Right.

Question 23

Coriolis Force acts at ‘____’ to the ‘____’ of the Wind in the Southern Hemisphere (2)?

Answer 23

• 90°.

- Left.

Question 24

True or False. The Coriolis Force is greatest to the Equator and zero to the Poles?

Answer 24

False. Greatest at Poles.

Question 25

Coriolis Force is ‘____’ to Wind Speed?

Answer 25

Proportional.

Question 26

Name two assumptions of the Geostrophic Wind Model?

Answer 26

- Wind blows above the Friction Layer. | - Wind blows parallel to straight Isobars.

Question 27

Name two forces that are part of the Geostrophic Wind Model?

Answer 27

- Pressure Gradient Force. | - Coriolis Force.

Question 28

For a particular Pressure Gradient Force, the Geostrophic Wind Speed increases as Latitude ‘____’?

Answer 28

Decreases.

Question 29

What is Buys Ballot’s Law for Surface Winds in both Hemispheres (2)?

Answer 29

- Northern Hemisphere, with your back to the Wind, the Low Pressure is to your Left. - Southern Hemisphere, with your back to the Wind, the Low Pressure is to your Right.

Question 30

What is the difference between Gradient Wind and Geostrophic Wind?

Answer 30

Gradient Wind takes into account the turning of Air Flow.

Question 31

Name two assumptions of the Gradient Wind Model?

Answer 31

- Wind blows above the Friction Layer. | - Wind blows along curved Isobars.

Question 32

Name three forces that are part of the Gradient Wind Model?

Answer 32

- Pressure Gradient Force. - Coriolis Force. - Centrifugal Force.

Question 33

True or False. The Centrifugal Force will increase the Pressure Gradient Force, thus increasing the Wind Speed around a High Pressure System?

Answer 33

True.

Question 34

True or False. The Centrifugal Force will decrease the Pressure Gradient Force, thus decreasing the Speed around a Low Pressure System?

Answer 34

True.

Question 35

For a particular Pressure Gradient Force, the Surface Wind Speed increases as Latitude ‘____’?

Answer 35

Decreases.

Question 36

Name three forces that are part of the Surface Wind Model?

Answer 36

- Pressure Gradient Force. - Coriolis Force. - Friction Force.

Question 37

For a particular Pressure Gradient Force, the Surface Wind Speed increases as Latitude ‘____’?

Answer 37

Decreases.

Question 38

In the Northern Hemisphere, as you climb from the surface to about 2,000 ft. the Wind Direction ‘____’ and ‘____’ in Speed. When descending towards the surface, the Wind ‘____’ and ‘____’ in Speed (4)?

Answer 38

- Veers. - Increases. - Backs. - Decreases.

Question 39

On Land, the Surface Wind will decrease by ‘____’ in Speed and deviate by ‘____’ (2)?

Answer 39

- 50%. | - 30°.

Question 40

In the Northern Hemisphere, the Surface Wind ‘____’ and ‘____’ during the day and ‘____’ and ‘____’ during the night (4)?

Answer 40

- Increases. - Veers. - Decreases. - Backs.

Question 41

True or False. The Surface Wind is stronger from 1500 than 0600?

Answer 41

False. Stronger at 0600.

Question 42

What is a Sea Breeze?

Answer 42

Wind from the Sea to the Land during the Day.

Question 43

True or False. Sea Breeze will be cooled and start to sink over Land?

Answer 43

False. It will be heated and start to rise.

Question 44

What time during the Day will Sea Breeze be at its maximum?

Answer 44

1500.

Question 45

Sea Breezes are ‘____’ Winds that blow ‘____’ Air from the Sea to the Land (2)?

Answer 45

- Onshore. | - Cooler.

Question 46

What is a Land Breeze?

Answer 46

Wind from the Land to the Sea during the Night.

Question 47

True or False. Land Breeze will be heated and start to rise over the Sea?

Answer 47

True.

Question 48

What time during the Day will Night Breeze be at its maximum?

Answer 48

Just after Sunrise.

Question 49

Land Breezes are ‘____’ Winds that only occur at Night?

Answer 49

Offshore.

Question 50

Name three types of Mountain Winds?

Answer 50

- Anabatic Winds. - Katabatic Winds. - Foehn Winds.

Question 51

What direction does Anabatic Winds move and how are they formed (2)?

Answer 51

- Up Sloping Terrain. | - Daytime Heating of the Mountain Slopes.

Question 52

Air in contact with the Slopes of the Mountain are warmed by?

Answer 52

Conduction.

Question 53

What is the difference between Anabatic and Valley Winds (2)?

Answer 53

- Anabatic Winds are warm, less dense air which flows up the slope. - Valley Winds are cooler and sink to the bottom of the Valley.

Question 54

What direction does Katabatic Winds move and how are they formed (2)?

Answer 54

- Down Sloping Terrain. | - Night Time cooling of the Mountain Slopes.

Question 55

If the cooler air at Night from Katabatic Winds fall below the Dew Point, what weather phenomenon can occur?

Answer 55

Valley Fog.

Question 56

Define how Antarctica Katabatic Winds are formed and their speed (2)?

Answer 56

- Deflected by Coriolis Force to form the Polar Easterlies. | - 100 kt.

Question 57

Name three local Katabatic European winds and their location?

Answer 57

- Mistral Winds = South Eastern France. - Tramontara Winds = Over the Pyrenees. - Bora Winds = East of Adriatic.

Question 58

Define Foehn Winds?

Answer 58

Local warm, dry wind which blows on the leeward side of a Mountain.

Question 59

With Foehn Winds, expect Cloud and Rain on the ‘____’ side and warm, dry clear skies on the ‘____’ side of the Mountain (2)?

Answer 59

- Upwind Side. | - Downwind Side.

Question 60

During Foehn Wind, what type of Stability is the Air?

Answer 60

Stable.

Question 61

The moist air rises at the rate of ‘____’ and descents to warm air at the rate of ‘____’ (2)?

Answer 61

- Saturated Adiabatic Lapse Rate. | - Dry Adiabatic Lapse Rate.