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PPL Course - (3) Navigation and Meteorology > Chapter 8.3 - Stability, Clouds and Precipitation > Flashcards

Chapter 8.3 - Stability, Clouds and Precipitation Flashcards

1
Q

What is defined as a stable atmosphere?

A

A parcel of air moving upwards returns to its original position.

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2
Q

What is defined as an unstable atmosphere?

A

A parcel of air moving upwards continues to rise rather than return to its original position.

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3
Q

What is defined as a neutrally stable atmosphere?

A

A parcel of air which remains displaced.

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4
Q

What is defined as adiabatic cooling?

A

A parcel of air which is cooled by the decrease in pressure, assuming no other heat energy is transferred.

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5
Q

What does DALR stand for?

A

Dry Adiabatic Lapse Rate.

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6
Q

Define DALR?

A

The rate at which the temperature of unsaturated air changes through the atmosphere.

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7
Q

What is the DALR?

A

-3°C per 1000ft.

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8
Q

What does SALR stand for?

A

Saturated Adiabatic Lapse Rate.

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9
Q

Define SALR?

A

The rate at which the temperature of saturated air changes through the atmosphere.

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10
Q

What is the SALR?

A

-1.5°C per 1000ft.

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11
Q

Stable air occurs when ELR is?

A

Less than the SALR.

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12
Q

Name two effects of a stable atmosphere?

A
  • Stratiform clouds.

- Poor visibility.

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13
Q

Unstable air occurs when ELR is?

A

Higher than the DALR.

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14
Q

Name two effects of a stable atmosphere?

A
  • Cumuliform clouds.

- Good visibility.

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15
Q

If the ELR falls between the SALR and DALR what factor is dependent in understanding the stability of the atmosphere?

A

Humidity.

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16
Q

True or False. The temperature lapse rate in the atmosphere varies depending on the surface?

A

True.

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17
Q

What is defined as a surface/radiation inversion layer?

A

When the air adjacent to the surface becomes colder than the air above.

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18
Q

What is defined as a turbulence inversion layer?

A

When dry air within a thin layer close to the ground is mixed by turbulence.

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19
Q

What is defined as a frontal inversion layer?

A

When two air masses of different temperatures meet, the cool air forces the warmer air aloft.

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20
Q

When will a frontal layer occur?

A

At the boundary between two air masses.

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21
Q

A subsidence inversion layer is associated with which weather phenomenon?

A

Anticyclone/High Pressure.

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22
Q

What effect would a decrease in density (when ascending through an inversion layer) have on an Aircraft?

A

Loss in lift and power.

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23
Q

What effect would a decrease in density (when ascending through an inversion layer) have on flight instruments?

A

The Airspeed Indicator will fluctuate.

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24
Q

True or False. A decrease in density (when ascending through an inversion layer) will have a major effect on the operation of an Aircraft?

A

False.

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25
Q

True or False. Reduced visibility can effect an inversion layer?

A

False. It affects the layer below.

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26
Q

What type of flights are affected by reduced visibility below an inversion?

A

Visual Flights.

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27
Q

True or False. Turbulence exists in an inversion layer?

A

False. As inversion layers are stable.

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28
Q

An Aircraft climbing/descending through an inversion layer will be subjected to an alteration in what?

A

Drift.

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29
Q

What the two main classifications of clouds?

A
  • Cumuliform.

- Stratiform.

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30
Q

Name three cloud groups and their height?

A
  • Low Cloud = surface to 8500ft.
  • Medium Cloud = 8500ft to 20 000ft.
  • High Cloud = 20 000ft and above.
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31
Q

What is the abbreviation and base of Stratus clouds?

A
  • ST.

- Base = 500/2000ft.

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32
Q

What is the abbreviation and base of Stratocumulus clouds?

A
  • SC.

- Base = 2000/5000ft.

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33
Q

What is the abbreviation and base of Cumulonimbus clouds?

A
  • CB.

- Base = 2000/5000ft.

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34
Q

What is the abbreviation and base of Towering Cumulus clouds?

A
  • TCU.

- Base = 2000/5000ft.

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35
Q

What is the abbreviation and base of Cumulus clouds?

A
  • CU.

- Base = 2000/5000ft.

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36
Q

What is the abbreviation and base of Altocumulus clouds?

A
  • AC.

- Base = 8500/20 000ft.

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37
Q

What is the abbreviation and base of Altostratus clouds?

A
  • AS.

- Base = 8500/20 000ft.

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38
Q

What is the abbreviation and base of Nimbostratus clouds?

A
  • NS.

- Base = 500/8500ft.

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39
Q

What is the abbreviation and thickness of Cirrocumulus clouds?

A
  • CC.

- Usually only a thin layer.

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40
Q

What is the abbreviation and thickness of Cirrostratus clouds?

A
  • CS.

- Usually only a thin layer.

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41
Q

What is the abbreviation and thickness of Cirrus clouds?

A
  • CI.

- Usually only a thin layer.

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42
Q

How many OKTAs are there in SKC?

A

0.

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43
Q

How many OKTAs are there in FEW?

A

1-2.

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44
Q

How many OKTAs are there in SCT?

A

3-4.

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45
Q

How many OKTAs are there in BKN?

A

5-7.

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46
Q

How many OKTAs are there in OVC?

A

8.

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47
Q

Cumuliform clouds have a large (horizontal/vertical) extent?

A

Vertical.

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48
Q

Stratiform clouds have a large (horizontal/vertical) extent?

A

Horizontal.

49
Q

Cumulonimbus clouds: Description?

A

Heavy and Dense.

50
Q

Cumulonimbus clouds: Process of Formation?

A

Convection.

51
Q

Cumulonimbus clouds (Flying Conditions): Weather (2)?

A
  • Thunderstorms/Lighting.

- Moderate/Heavy Showers.

52
Q

Cumulonimbus clouds (Flying Conditions): Turbulence?

53
Q

Cumulonimbus clouds (Flying Conditions): Visibility?

A

Less than 20m.

54
Q

Cumulonimbus clouds (Flying Conditions): Effect on VFR?

A

Dangerous.

55
Q

True or False. Cumulonimbus is one of the most dangerous clouds?

56
Q

Cumulus/Towering Cumulus clouds: Description?

A

Detached clouds.

57
Q

Cumulus/Towering Cumulus clouds: Process of Formation?

A

Convection.

58
Q

Cumulus/Towering Cumulus (Flying Conditions): Weather (2)?

A
  • CU = Nil.

- TCU = Moderate/Heavy Showers.

59
Q

Cumulus/Towering Cumulus (Flying Conditions): Turbulence (2)?

A
  • CU = Light to Moderate.

- TCU = Moderate to Severe.

60
Q

Cumulus/Towering Cumulus (Flying Conditions): Visibility?

A

0 to 200m.

61
Q

Cumulus/Towering Cumulus (Flying Conditions): Effect on VFR?

62
Q

Stratocumulus clouds: Description?

A

Grey/Whitish Patch/Sheet clouds.

63
Q

Stratocumulus clouds: Process of Formation?

A

Turbulence.

64
Q

Stratocumulus clouds (Flying Conditions): Weather?

A

Nil but can produce drizzle.

65
Q

Stratocumulus clouds (Flying Conditions): Turbulence?

A

Light to Moderate.

66
Q

Stratocumulus clouds (Flying Conditions): Visibility?

A

30 to 200m.

67
Q

Stratocumulus clouds (Flying Conditions): Effect on VFR?

A

Significant.

68
Q

Stratus clouds: Description?

A

Grey clouds.

69
Q

Grey clouds.

A

Turbulence.

70
Q

Stratus clouds (Flying Conditions): Weather?

A

Occasional Drizzle.

71
Q

Stratus clouds (Flying Conditions): Turbulence?

A

Nil to Light.

72
Q

Stratus clouds (Flying Conditions): Visibility?

A

10 to 200m.

73
Q

Stratus clouds (Flying Conditions): Effect on VFR?

A

Dangerous.

74
Q

Altostratus clouds: Description?

A

Greyish/Bluish clouds.

75
Q

Altostratus clouds: Process of Formation?

A

Widespread ascent and frontal lifting.

76
Q

Altostratus clouds (Flying Conditions): Weather (2)?

A
  • Thin AS = Generally nil, can produce light rain in Virga.

- Thick AS = Can produce light, intermittent/continuous rain.

77
Q

Altostratus clouds (Flying Conditions): Turbulence (2)?

A
  • Thin AS = Nil to Light.

- Thick AS = Can be Moderate.

78
Q

Altostratus clouds (Flying Conditions): Visibility?

A

300 to 1000m.

79
Q

Altostratus clouds (Flying Conditions): Effect on VFR?

80
Q

Altocumulus clouds: Description?

A

Layer/Patches of cloud.

81
Q

Altocumulus clouds: Process of Formation?

A

Turbulence and Convection.

82
Q

Altocumulus clouds (Flying Conditions): Weather?

83
Q

Altocumulus clouds (Flying Conditions): Turbulence?

84
Q

Altocumulus clouds (Flying Conditions): Visibility?

85
Q

Altocumulus clouds (Flying Conditions): Effect on VFR?

86
Q

Nimbostratus clouds: Description?

A

Dark grey cloud covering the whole sky.

87
Q

Nimbostratus clouds: Process of Formation?

A

Widespread ascent and frontal lifting.

88
Q

Nimbostratus clouds (Flying Conditions): Weather?

A

Moderate/Heavy continuous rain.

89
Q

Nimbostratus clouds (Flying Conditions): Turbulence?

90
Q

Nimbostratus clouds (Flying Conditions): Visibility?

A

20 to 100m

91
Q

Nimbostratus clouds (Flying Conditions): Effect on VFR?

A

Significant/Dangerous.

92
Q

True or False. Nimbostratus clouds are the only clouds to produce continuous rain?

93
Q

Cirrocumulus clouds: Description?

A

Thin, white patch/sheet/layer of cloud.

94
Q

Cirrocumulus clouds: Process of Formation?

A

Turbulence.

95
Q

Cirrocumulus clouds (Flying Conditions): Weather?

96
Q

Cirrocumulus clouds (Flying Conditions): Turbulence?

A

Nil to Light.

97
Q

Cirrocumulus clouds (Flying Conditions): Visibility?

98
Q

Cirrocumulus clouds (Flying Conditions): Effect on VFR?

99
Q

Cirrostratus clouds: Description?

A

Transparent whitish veil.

100
Q

Cirrostratus clouds: Process of Formation?

A

Widespread ascent and frontal lifting.

101
Q

Cirrostratus clouds (Flying Conditions): Weather?

102
Q

Cirrostratus clouds (Flying Conditions): Turbulence?

A

Nil to Light.

103
Q

Cirrostratus clouds (Flying Conditions): Visibility?

A

Over 1000m.

104
Q

Cirrostratus clouds (Flying Conditions): Effect on VFR?

105
Q

Cirrus clouds: Description?

A

Cirrus clouds: Description?

106
Q

Cirrus clouds: Process of Formation?

A

Widespread ascent and frontal lifting.

107
Q

Cirrus clouds (Flying Conditions): Weather?

108
Q

Cirrus clouds (Flying Conditions): Turbulence?

A

Nil to occasionally light.

109
Q

Cirrus clouds (Flying Conditions): Visibility?

A

Over 1000m.

110
Q

Cirrus clouds (Flying Conditions): Effect on VFR?

111
Q

Define Precipitation?

A

Any aqueous deposit that falls to the ground.

112
Q

Name four products of Precipitation?

A
  • Rain.
  • Drizzle.
  • Snow.
  • Hail.
113
Q

Name three classifications of Precipitation?

A
  • Showers.
  • Intermittent Precipitation.
  • Continuous Precipitation.
114
Q

Which clouds are associated with Shower Precipitation (2)?

A
  • Cumulonimbus.

- Cumulus.

115
Q

How long does Shower Precipitation last for?

A

15 to 30 minutes.

116
Q

Which clouds are associated with Intermittent Precipitation?

A

Stratiform.

117
Q

How long does Intermittent Precipitation last for?

A

Up to several hours.

118
Q

Which cloud is associated with Continuous Precipitation?

A

Nimbostratus.

119
Q

How long does Continuous Precipitation last for?

A

Several hours or more.

PPL Course - (3) Navigation and Meteorology (23 decks)

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