Pressure Systems and Wind Flashcards

1
Q

The force per unit area exerted by the weight of the air lying above that level.

A

Atmospheric Pressure

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2
Q

What are the 2 common methods of measuring pressure?

A
  1. Digital Barometer
  2. Aneroid Barometer
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3
Q

What are the units used for pressure in aviation?

A
  1. Inches of Mercury (inHg)
  2. Hectopascals (hpa)
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4
Q

Type of barometer that measures the atmospheric pressure electronically and displays the results digitally.

A

Digital Barometer

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5
Q

Type of barometer that is a partially evacuated flexible metal cell that contracts with increasing pressure and expands with decreasing pressure. The change is registered on a scale by means of a needle and coupling mechanism.

A

Aneroid Barometer

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6
Q

The weight of the air above the airport that is measured.

A

Station Pressure

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7
Q

The station pressure plus the weight of the fictitious column of air between the station and mean sea level.

A

Mean Sea Level Pressure

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8
Q

Lines drawn on a Surface Weather Map joining places of equal MSL Pressure.

A

Isobars

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9
Q

What is the interval between Isobars on a Surface Weather Chart?

A

4 Hectopascals

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10
Q

Areas of MSL pressure surrounded on all sides by higher pressure.

A

Low Pressure

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11
Q

What are other names for Low Pressure areas?

A
  1. Depressions
  2. Cyclones
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12
Q

The curvature of isobars to the left if you were to stand with lower pressure to your left.

A

Cyclonic Curvature

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13
Q

Areas of pressure surrounded on all sides by lower pressure.

A

High Pressure

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14
Q

What is another name for High Pressure areas?

A

Anticylones

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15
Q

The curvature of isobars to the right if you were to stand with lower pressure to your left.

A

Anticyclonic Curvature

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16
Q

Elongated areas of low pressure with the lowest pressure along the line of maximum cyclonic curvature.

A

Troughs

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17
Q

Elongated areas of high pressure with the highest pressure along the line of maximum anticyclonic curvature.

A

Ridges

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18
Q

Neutral areas between 2 highs and 2 lows.

A

Cols

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19
Q

The rate of rise or fall of pressure at a particular location.

A

Pressure Tendency

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20
Q

The force that causes air to move from high pressure to low pressure.

A

Pressure Gradient Force

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21
Q

What determines the strength of the Pressure Gradient Force?

A

Pressure difference over the area

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22
Q

Isobars that are spaced closely together are called what?

A

Steep or Strong

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23
Q

Isobars that are far apart are called what?

A

Weak or Flat

24
Q

A force that is a result of the earth’s rotation. It causes air in motion to deflect.

A

Coriolis Force

25
Q

Which way does the Coriolis force deflect in the northern hemisphere?

A

Right Deflection

26
Q

Which way does the Coriolis force deflect in the southern hemisphere?

A

Left Deflection

27
Q

What determines the strength of the Coriolis Force?

A

Speed of the Object (Air)

28
Q

The strength of the Coriolis force at the equator vs the poles.

A

Zero at the equator
Maximum at the Poles

29
Q

When Coriolis Force balances the Pressure Gradient Force, this is called?

A

Geostrophic Wind

30
Q

“If you stand with your back to the wind in the northern hemisphere, low pressure will be on your left.”

A

Buys-Ballot Law

31
Q

What are the 3 effects on wind?

A
  1. Latitude
  2. Curvature
  3. Friction
32
Q

What type of force is in the curvature effect?

A

Cetrifugal Force (cf)

33
Q

What pressure area is the centrifugal force is acting the same direction as the pressure gradient force?

A

High Pressure

34
Q

What pressure area is the centrifugal force acting opposite of the pressure gradient force?

A

Low Pressure

35
Q

How does Friction affect wind?

A

Reduce wind speed, resulting in less affect of Coriolis Force.

36
Q

Rapid peaks and lulls in the wind speed is called?

A

Gusts or Squalls

37
Q

Clockwise change in direction.

A

Veer

38
Q

Counterclockwise change in direction.

A

Back

39
Q

Rate at which air spirals inwards and upwards increases.

A

Deepening Low

40
Q

Rate at which air spirals downwards and outwards increases.

A

Intensifying High

41
Q

What causes the link between the earth’s surface and the free flowing air above to disappear?

A

Nocturnal Inversion

42
Q

When are winds usually stronger and gustier?

A

During the day

43
Q

What kind of flow results with stable air flowing smoothly over terrain with little turbulence but with marked vertical wind shear?

A

Laminar Flow

44
Q

What kind of flow results with stable air and fast wind speed, or the air flows over a sharp ridge?

A

Turbulent Flow

45
Q

These types of winds flow out of the mountain valleys and over the ocean on the West Coast reaching speeds of up to 80kts and creating hazardous shear and turbulent conditions.

A

Funnel Winds

46
Q

Wind that flows up a slope or a valley during the day.

A

Anabatic Winds

Valley Wind

47
Q

Downslope wind that may consist of either a warm or cold flow of air down a slope and may develop into an extremely strong wind with dangerous shears.

A

Katabatic Winds

Mountain Wind

48
Q

What are the two types of Katabatic Winds?

A
  1. Glacier (Cold)
  2. Chinook (Warm)
49
Q

Between what months is common for the chinook of Alberta to occur?

A

September and April

50
Q

What is the range of the return circulation of a Sea Breeze?

A

1,500ft to 3,000ft above the surface

51
Q

A “sheet” of strong winds some thousands of miles long, hundreds of miles wide and hundreds of feet thick.

A

Low-Level Jet

52
Q

This type of wind can occur due to a nocturnal inversion where the wind near the top of the inversion increases to speeds greater than that indicated by the isobar spacing on a weather map.

A

Low-Level Nocturnal Jet Stream

53
Q

The level of maximum wind varies from about (?ft) to (?ft) above ground.

A

700ft to 2,000ft

54
Q

Surface wind during the Day.

A
  1. Wind Increases
  2. Gusty
  3. Veers
55
Q

Surface winds during the night.

A
  1. Wind Decreases
  2. Smooth
  3. Backs