Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CPL > Meteorology > Flashcards

Meteorology Flashcards

1
Q

Approximately how much water is present in the tropopause?

A

0-5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the percentage of gases in the atmosphere?

A

78% Nitrogen
21% Oxygen
1% other gases (argon, CO2, Neon, helium etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the height of the polar tropopause?

A

25000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the height of the tropical/equator tropopause?

A

60000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What changes to the height of the tropopause over summer?

A

Height will increase with increase of temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the ISA height of tropopause?

A

36090 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the temperature of the polar tropopause?

A

Approx -40 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the temperature of the tropical/equator tropopause?

A

Approx -80 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the ISA temperature of the tropopause?

A

-56.5 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens to temperature in the stratosphere?

A

In lower layers temp is steady, increases near the top layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why does the temperature increase as we gain height in the stratosphere?

A

Due to the absorption of UV radiation and increase of ozone at higher levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How high does the stratosphere go?

A

To 120000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is ozone and does it do?

A

Colourless, corrosive and irritating gas that absorbs UV rays, shielding humans from the damaging rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the ISA pressure?

A

1013.25 hPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the ISA temperature?

A

15 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does temperature decrease at?

A

1.98 degrees per 1000 ft up to 36090 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

After 36090 feet, what happens to temperature according to ISA?

A

From 36090 to 65617 feet, temp is constant -56.5 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

After 65617 feet, what happens to temperature according to ISA?

A

From 65617 to 104987 feet, temp increases at 0.3 degrees per 1000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Above what height will the ozone levels exceed humans tolerable limits?

A

50000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can be used to assist pilots break down ozone to an acceptable level?

A

Heat of compressor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the advantages of more dense air?

A

Lift required generated at lower speed
Greater engine power due to greater mass of fuel/air taken to cylinders
Breathing is easier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to density and pressure as we gain height?

A

Pressure decreases, density decreases as number of molecules in cubic meter decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

At what height is the density approximately half that at sea level?

A

18000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

At what rate does pressure fall?

A

1hPa per 30 feet (up to 5000ft AMSL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where is most of the mass of the atmosphere contained and why?

A

Near the surface due to gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the three ways heat can be transferred?

A

Radiation
Absorption
Conduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Is air a good conductor of heat?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is convection?

A

Mass of air is heated at the earths surface which will expand, become less dense and rise.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is thermal convection?

A

Rising air carrying heat energy into atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is advection?

A

Horizontal motion of air. AKA wind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is ‘sea breeze’?

A

Solar radiation heating earths surface. Air in contact with surface becomes hot by conduction and rises. This creates low pressure over the land, and the high pressure from the sea will flow towards land

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

When is the sea breeze strength the greatest?

A

Mid afternoon on a hot day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is land breeze?

A

During the night, earth surface cools by radiating heat into space. Earth surface cools quicker than the sea. (higher pressure over land and lower pressure over sea). Results in cooler air from land blows towards sea.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Which is generally stronger, land or sea breeze?

A

Sea breeze

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are katabatic winds?

A

Cool parcels of air sinking down the slopes of mountains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How do katabatic winds occur?

A

Earth surface cools through terrestrial radiation. Density becomes greater than lower air (more dense air is heavier) causes air to flow down slope due to gravity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the ideal conditions for katabatic winds?

A

During night on a high plateau sloping steeply down towards low terrain (i.e. coast).
Clear skies over plateau
Relatively warm surrounding air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

When are katabatic winds usually strongest?

A

Strongest at dawn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are anabatic winds?

A

Winds blowing up sloping terrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Why do anabatic winds occur?

A

Surface on slope heated and rises. Wind blows up to replace rising warm air.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which is stronger, anabatic or katabatic winds?

A

Katabatic winds due to gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Where are anabatic winds likely to occur?

A

Westward slopes during summer afternoons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are Fohn winds?

A

Warmer drier airflow on the leeside of the mountain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How are Fohn winds caused?

A

Highly moist air rising up mountain range having a high dew point temperature. If the air is cooled before reaching the top of the mountain, cloud forms on windward side. If precipitation occurs, moisture is removed from airflow causing air to be drier as cloud descends on lee side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are low level jet streams?

A

High pressure circulating anti clockwise along Australian continent.
Crowds isobars together, increases surface pressure gradient causing wind speeds to increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Freed of surface friction, gradient winds can reach what speeds at 2000 feet?

A

40-50 kts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Where are the greatest winds and when do they occur for low level jet streams?

A

West of great dividing range about dawn (0600 to 0900 LMT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Which direction are low level jet streams usually from?

A

From south

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the three states water exists?

A

Ice
Liquid
Vapour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

In order from highest to lowest state, rank the water states.

A

Vapour
Liquid
Ice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Solid to liquid?

A

Melting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Liquid to vapour?

A

Evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Solid to vapour?

A

Sublimation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Vapour to liquid?

A

Condensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Liquid to solid?

A

Solidification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Vapour to solid?

A

Deposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What is meant by the term ‘saturated’?

A

When amount of water vapour present is such that parcel of air is unable to hold more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

How does change in temperature affect vapour state?

A

Decrease in temperature reduces ability to hold water in vapour state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is relative humidity?

A

How close air is to saturation

Water vapour present in air to mass of water vapour which would cause saturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What happens to the vapour possible as temperature is decreased?

A

It decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What happens at 100% humidity?

A

You have reached your dew point temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is dew point temperature?

A

Temperature at which saturation occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is the environmental lapse rate?

A

Temperature drop of 2 degrees / 1000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What does the ELR determine?

A

Stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

How is a cloud formed?

A

When a parcel of air is cooled to its dew point temperature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is the dry adiabatic lapse rate?

A

3 degrees / 1000 feet.

Rate at which parcel of dry air cools as it ascends

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What is saturated adiabatic lapse rate?

A

1.5 degrees / 1000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What conditions are associated with a low ELR?

A

Stable conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What conditions are associated with a high ELR?

A

Unstable conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are the conditions like in a stable environment?

A 
ELR low
High pressure system
Stratiform clouds at high level
Precipitation (if any) is steady
Poor visibility
Smooth conditions
Little to no turbulence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What are conditions like in an unstable environment?

A 
ELR high
Low pressure system/trough
Warm air continues to rise
Turbulent (especially in thermals)
Cumuliform clouds
Showery rain if precipitation
Good visibility inbetween showers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What happens to a parcel of air that is warmer than it’s surrounding environment?

A

Because it is less dense, will rise until encounters environment of same temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What happens to a parcel of air that is cooler than it’s surrounding environment?

A

Because it is more dense, it will sink until it encounters environment of same temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What are the triggers for vertical motion of air?

A

Convection
Orographic Uplift
Turbulence and Mixing
Frontal Uplift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What is convection?

A

Cold air going over a warm surface. The air is warmed from below and becomes less stable.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What happens in orographic uplift?

A

Humid air rises over mountain range, cools as gains height and rises. When dew point reaches clouds will form. As it descends, warms and dissipates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What is frontal uplift?

A

When cold and warm air meet, heavier cold air remains at the surface forcing lighter warmer air to rise over it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What is a front?

A

The boundary between cold and warm front

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

How are cumuliform clouds formed?

A

Formed by unstable warm air rising and cooling.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What are rain bearing clouds called?

A

Cumulonimbus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What temperature are stratiform/stratus clouds

A

Equal to or cooler than environment air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What is the base and tops for stratus clouds?

A

Base below 1000 feet and tops above 20000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What are the high level clouds and what are their bases above?

A

Cirrocumulus
Cirrostratus
Cirrus
20000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

What are the medium level clouds and what are their bases between?

A

Altocumulus
Altostratus
Bases between 7500 and 20000 feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What are low level clouds and what are their bases below?

A 
Cumulus
Stratus
Stratocumulus
Nimbostratus
Cumulonimbus
Bases below 7500 feet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What are cirrus clouds like?

A

High level with little turbulence and little to no icing risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

What are thin altostratus clouds like?

A

‘Bluish’ with little turbulence entering/leaving the cloud. Some rime ice and virga may be encountered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

What are large cumulus (Cu) clouds like?

A

Low level ‘cauliflower’ shaped. Shower of rain, moderate to severe turbulence and a definite icing risk. Clear ice above freezing height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Describe cumulonimbus (Cb) clouds

A

Very large vertical extent with tops ‘anvil’ shaped.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What conditions are likely in cumulonimbus (Cb) clouds?

A

Thunderstorms, lightning, showers of rain, snow or hail.
Severe turbulence, violent entering/leaving
Definite icing risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What is fog?

A

‘Cloud’ on ground
Visibility below 1000m
Nil turbulence or icing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

Which clouds will there be ice present?

A

As, Ac Lenticularis and castellarius, Large Cu, Sc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Which clouds will produce moderate turbulence?

A

Ac lenticularius and castellarius, Cu, Cb, Sc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

How long do individual showers usually last?

A

15-30 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What three conditions need to occur for a thunderstorm to happen?

A

Trigger
Instability
High humidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What are the three stages of thunderstorms?

A

Growing
Mature
Dissipating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What happens in the growing stage of the thunderstorm?

A

Up-draughts up to 5000fpm

Water droplets carried higher and higher by up-draughts and can freeze if carried above freezing level.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

How long does the growing stage last?

A

10-20 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

What happens in the mature stage of the thunderstorm?

A

Up draughts and down draughts
Up draughts become weaker
Precipitation becomes too large for updraughts and rain commences.
extreme turbulence and windshear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

How long does the mature stage last?

A

20-40 mins

101
Q

What happens in the dissipating stage of the thunderstorm?

A

Cessation of updraughts

Cloud edges appear ragged and begin to evapourate

102
Q

How long does the dissipating stage last?

A

30 mins

103
Q

Does lightning pose a threat to flying?

A

Not to humans inside plane. May cause damage to radios and/or electronic equipment

104
Q

At what height can hail occur during a storm?

A

10000-20000 feet

105
Q

What is a microburst?

A

Short blast of cold air causing drastic change in vertical and horizontal wind speeds

106
Q

What is an indicator that microburst may be present?

A

Virga

107
Q

What is a tornado?

A

Rotating column of air from ground to base of a large Cu or Cb

108
Q

What is a funnel cloud?

A

Tornado that doesn’t reach the ground

109
Q

Is the central pressure higher or lower than surrounding air in a tornado?

A

Lower

110
Q

How high can dust devils go?

A

Up to 7000 feet AGL

111
Q

How long do dust devils last?

A

Less than 30 mins

112
Q

How big in diameter are dust devils?

A

10-300 feet

113
Q

If caught in a dust devil, what speed should you maintain?

A

Turbulence penetration speed

114
Q

What is the worst kind of turbulence?

A

Frontal turbulence

115
Q

Where do mountain waves occur?

A

On the Lee side of a mountain

116
Q

What are the conditions for mountain waves to occur?

A

Lower half of troposphere
Mountain range greater than 1000 feet
Wind speed greater 25 knots at mountain top
Inversion or stable layer at the top

117
Q

How should you avoid mountain waves?

A

In valley, keep downwind when air is rising

If lenticular clouds are present, fly upwind of them

118
Q

What is the Runway Visual Range?

A

Maximum distance at takeoff or landing at which runway can be seen from position corresponding to average eye level of pilot at touchdown

119
Q

How is the RVR derived?

A

Instrumentally derived

120
Q

What is fog?

A

Very small water dropletts which reduce visibility to below 1000m

121
Q

What is the relative humidity in fog?

A

Approx 100%

122
Q

What temp can ice fog form?

A

-20degrees

123
Q

What is mist?

A

Very small water droplets which reduce visibility to 1000m or more

124
Q

What is relative humidity in mist?

A

Approx 95%

125
Q

How is radiation fog formed?

A

Air cooled below dew point temperature, losing heat by radiation

126
Q

What are the conditions required for radiation fog?

A 
Cloudless night
Cold land surface
Moist air
Small temperature/dewpoint
High humidity
Light winds (5-7 kts)
127
Q

If the conditions are set for fog but the temperature is above freezing, what may occur?

A

Dew

128
Q

If the conditions are set for fog but the temperature is below freezing, what may occur?

A

Frost

129
Q

If the winds are above 7 knots but set for fog conditions, what may occur

A

Stratus clouds near ground

130
Q

What is advection fog?

A

Warm moist air flowing across cold surface. If the temp is reduced to dew point, fog forms

131
Q

Which is thicker/more persistent, advection or radiation fog?

A

Advection fog

132
Q

What is upslope fog?

A

Moist air up a slope will cool adiabatically and if it cools below its dewpoint, fog forms

133
Q

What happens if wind stops during upslope fog?

A

Fog disipates

134
Q

What is an inversion?

A

Layer of atmosphere in which temperature increases with increase in height

135
Q

What are the three common types of inversions?

A

Surface/radiation
Subsidence
Frontal

136
Q

What is the conditions like in the lower layers of an inversion?

A

Smooth but poor visibility

137
Q

How does radiation inversion form?

A

Forms at night by cooling of ground. Ground radiates heat to atmosphere and lower layers of air immediately cooled by absorption to ground

138
Q

What conditions are required for radiation inversion?

A

Clear sky at night
Light wind
Suitable surface to promote radiation cooling

139
Q

How deep can subsidence inversion be?

A

500 feet deep

140
Q

What are the flying conditions like in an inversion?

A

Vertical windshear when climbing or descending through inversion
Gain thrust, lift and power descending into inversion
Turbulence
Cloud under inversion
Visibility better above layer

141
Q

In summer, which direction does global circulation move?

A

Moves south

142
Q

In winter, which direction does global circulation move?

A

Moves north

143
Q

What direction does anticyclone move and what sort of system is it?

A

A high pressure system that moves anticlockwise

144
Q

What is surface pressure?

A

Weight of air pressing down from above. When it cant descend any further it becomes divergent

145
Q

What happens to air as it rises?

A

Reduction in surface pressure
Carries moist air with it
Expands and cools

146
Q

What are low pressure systems, convergent or divergent?

A

Convergent

147
Q

What do isobars join?

A

Equal pressure

148
Q

What is a ridge?

A

Elongated finger of high pressure, wind turns sharply to the left

149
Q

What is a trough?

A

Elongated finger of low pressure, wind turns sharply to the right

150
Q

What is a col and what are the condition like?

A

Area between two highs and two lows. Conditions are light and variable

151
Q

How does air move, low to high or high to low?

A

High to low

152
Q

What is the rate of change of pressure?

A

Pressure gradient

153
Q

What happens with a steeper pressure gradient?

A

Means winds are faster

154
Q

What do closely spread isobars indicate?

A

Strong winds

low pressure

155
Q

What do widely spread isobars indicate?

A

Light winds

High pressure

156
Q

What direction does the pressure gradient act to the isobars?

A

Acts at right angle

157
Q

Which has a greater rotational velocity, pole or equator?

A

Equator

158
Q

Which direction does rotation velocity appear to turn in southern hemisphere?

A

To the left

159
Q

What happens with a faster pressure gradient/airflow?

A

Coriolis force is stronger

160
Q

Is there a coriolis force within 5 degrees of equator?

A

No

161
Q

What happens when pressure gradient equals coriolis force?

A

Air flows parallel to isobars

Called geostrophic wind

162
Q

Where will the wind be blowing FROM if you’re flying towards a low pressure system?

A

From the right

163
Q

Where will the wind be blowing FROM if you’re flying towards a high pressure system?

A

From the left

164
Q

What is wind following curved isobars called?

A

Gradient wind

165
Q

What is wind following strait isobars called?

A

Geostrophic winds

166
Q

What will the pressure and wind direction be if CF is greater than PG?

A

High and anticlockwise

167
Q

What will the pressure and wind direction be if PG is greater than CF?

A

Low and clockwise

168
Q

At what height will the wind follow the isobars the closest?

A

About 3000 feet where it is clear of surface friction

169
Q

Where is the cyclone most destructive?

A

Forward left quadrant

170
Q

Which cloud type is associated with heavy continuous rain?

A

Nimbostratus

171
Q

In which temperature range is clear ice likely to be most severe?

A

0 to -15

172
Q

What are squall lines associated with?

A

Thunderstorms

173
Q

When environmental temperature increase with height, said to be what condition?

A

Stable

174
Q

Fast moving cold front may be recognised by?

A

Broken cumulus clouds and rain showers

175
Q

What happens to IAS and rate of descent with sudden decrease in headwind?

A

Decrease in IAS

Increase in rate of descent

176
Q

What is conditional stability?

A

Saturated air is unstable

Unsaturated air is stable

177
Q

If you stand with you back to the wind in the southern hemisphere, where will the low pressure be?

A

Low pressure on right

178
Q

What are the three conditions for ice to form?

A

Must be visible moisture
Temperature at or below 0 degrees
Airframe temp must be below 0 degrees

179
Q

What are the worst icing conditions?

A

Near freezing level in heavy stratified clouds or in heavy rain

180
Q

How is rime ice formed?

A

Small supercooled droplets collide with leading edges have no time to ‘splash’ or spread across skin

181
Q

What is the temperature range for rime ice?

A

0 to -40 however it is most common from -10 to -20

182
Q

What cloud types are you likely to encounter rime ice?

A

Thin altostratus
altocumulus
Near top of large cumulus

183
Q

When is clear ice likely to form?

A

Flying through freezing rain which consist of large droplets.
Large droplets take longer to freeze so they spread

184
Q

What temperature range is clear ice likely to form?

A

5 to -15 degrees but most common in 0 to -10

185
Q

What cloud types is clear ice found in?

A

Thick altostratus
Thick altocumulus
Just above freezing level of large cumulus, cumulonimbus or nimbostratus

186
Q

How is hoar frost formed?

A

Cold soaked aircraft enters layer of warmer humid air, water vapour skips liquid state and goes straight to solid (deposition)

187
Q

What does frost on the airframe do to surface friction drag, total drag, stall AoA and stall speed?

A

Surface Friction and Total drag increased
Stall AoA decreased
Stall speed increased

188
Q

What are the three classifications of icing?

A

Light (FBL)
Moderate (MOD)
Severe (SEV)

189
Q

What should you do if you experience light (FBL) icing?

A

No change of track or altitude is necessary. No speed is lost

190
Q

What should you do if you experience moderate (MOD) icing?

A

Change of heading/altitude considered desirable.

Airspeed may be lost

191
Q

What should you do if you experience severe (SEV) icing?

A

Change of heading/altitude necessary

Ice builds up and seriously affects performance and manoeuvrability of a/c

192
Q

What direction is the trade wind in the southern hemisphere?

A

South easterly

193
Q

What are the trade wind characteristics?

A 
Blows with consistent velocity
Weaker at lower altitudes 
Generally stable under subsidence inversion of anticyclone
Air moist in lower levels
Relative humidity high at surface 
Air is dry above inversion
194
Q

What season is trade winds responsible for in Australia?

A

Dry season of north australia

195
Q

Generally, when does monsoon affect Australia?

A

Between December and April

196
Q

What direction winds are there in monsoon?

A

North westerly

197
Q

Which direction is the ‘roaring forties’?

A

Westerly towards sub polar low

198
Q

What conditions for the roaring forties produce?

A

Wet windy winters

199
Q

What is the inter-tropical convergence zone (ITCZ)?

A

North east or south east trade winds approach each other, causing vigorous convergence in narrow zone

200
Q

What conditions do the ITCZ produce?

A

Violent weather
Thunderstorms
Torrential rain
Wind squalls

201
Q

What conditions are associated with El Nino in eastern Australia?

A

Drier conditions

202
Q

What are the conditions for tropical cyclones to form?

A

Warm tropical oceans about 28 degrees Celsius

Abundant water vapour

203
Q

Can cyclones form at the equator? Why/why not?

A

No because Coriolis force is 0 at the equator.

204
Q

What are the stages of a cyclone?

A

Formative
Immature
Matture
Decaying

205
Q

In what stage and where are the strongest winds for a cyclone?

A

Mature stage

Forward left quadrant

206
Q

What happens to the pressure gradient in a cyclone as the centre approaches?

A

Gradually gets steeper

207
Q

What are cyclones formed from?

A

Thunderstorms

208
Q

What are the conditions like in the eye of the cyclone?

A

Light and variable

Lowest surface pressure

209
Q

What clouds are associated with cyclones?

A

Nimbostratus with spiral bound cumulus and cumlionimbus

210
Q

What latitude do cyclones generally form?

A

Between 5 and 15 degrees south

211
Q

What does the surface sea temperature need to be for a cyclone to form?

A

Approximately 28 degrees

212
Q

What is the surface pressure around the eye?

A

Approx 900hPa

213
Q

What clouds are associated with a cold front?

A

Cumulus and cumulonimbus

214
Q

What weather conditions are associated with a cold front?

A

Thunderstorms, line squalls, severe turbulence and windshear

215
Q

What will indicate a cold front?

A

Drop in temperature
Wind backing south west
Cumulus and cumulonimbus clouds

216
Q

What will indicate a warm front?

A

Air temperature rise
Dewpoint temperature will be higher
Unstable air
wind backs north west

217
Q

What is an occluded front?

A

When a cold front overtakes a warm front

218
Q

What are subsidence inversions?

A

Anticyclones of high pressure

Air in top layers sinks with greater adibatic warming than lower layers

219
Q

What are the cloud levels in aerodrome and trend forecasts?

A

Above aerodrome level

220
Q

What are cloud levels for forecasts other than aerodrome and trend forecasts?

A

Above Mean sea level or flight level

221
Q

What is an isotherm?

A

Line on synoptic chart joining equal temperature

222
Q

The amount of water vapour that air can hold largely depends on what?

A

Air temperature

223
Q

What situation is advection fog likely to form?

A

Warm moist air mass moving over cold surface

224
Q

What type of clouds are associated with anticyclones?

A

Stratocumulus and stratus

225
Q

What are the processes by which moisture is added to unsaturated air?

A

Heating and condensation

226
Q

Clouds, fog or dew will always form when?

A

Water vapour condenses

227
Q

What are the locations on the pca?

A

Identifiers used to divide area

228
Q

What are ‘critical locations’ in ARFOR?

A

Critical for vfr flight in adverse weather

229
Q

What does 12/11 on METAR mean?

A

Temp is 12

Dew point is 11

230
Q

The equatorial trough moves further north than south because?

A

Mid summer surface temp are higher at any given latitude in northern hemisphere because of greater land mass

231
Q

What is the layer of atmosphere in which most of the convection takes place?

A

Troposphere

232
Q

The belt of high pressure of Australia during winter is called?

A

Sub tropical ridge

233
Q

Monsoon trough features extensive cloud and weather because?

A

Converging airstream rises over warm ocean due to intensity of solar radiation

234
Q

There is little convection within the stratosphere because?

A

Air at top layer is cooler than air at bottom

235
Q

Pressure gradine force acts in which direction and to/from which system?

A

At right angle towards low pressure

236
Q

Surface wind compared to gradient wind backs or veers and faster or slower?

A

Veers to right and slower

237
Q

What does surface friction cause in relation to Coriolis force?

A

Increase CF

238
Q

Compared to gradient wind, surface wind in Southern Hemisphere is found to be?

A

Further to right in both highs and lows

239
Q

For a katabatic wind to form, there must be?

A

A surface inversion

240
Q

Strong horizontal wind shear can be found where?

A

Above strong surface inversion

241
Q

Light wind beneath radial inversion will cause inversion to become?

A

Weaker but deeper

242
Q

Low level jet streams can be hazardous because they produce?

A

Strong horizontal wind shear near surface

243
Q

What variations in wind and temperature normally occur with passage of cold front?

A

Wind backs and temperature falls

244
Q

Low cloud moving rapidly in warm air ahead of a cold front will likely to produce what?

A

Squall line

245
Q

What happens to the central pressure in a tropical cyclone during the mature stage?

A

Remains constant

246
Q

A stable layer of air near the height of a ridge will produce what?

A

Mountain wave activity

247
Q

There is little vertical development of cloud within the south east trade winds because?

A

Presence of trade wind inversion

248
Q

Dust storms are most likely to produce which hazards with regards to visibility and heights?

A

Severe visibility restriction over wide spread area to heights above 10000feet

249
Q

What is likely to happen during cumulus (growing) stage of thunderstorm?

A

Severe airframe icing

CPL (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions