Meteorology Quiz & Test Flashcards
(121 cards)
1
Q
What is the composition of our atmosphere?
A
78% Nitrogen, 21% Oxygen, water vapour 0 to 3%, carbon dioxide 0.03%.
2
Q
What commences a change of state in a substance (i.e. water)?
A
When water changes state, energy in the form of heat is either released or absorbed.
3
Q
What is moisture content?
A
The ability of the atmosphere to hold moisture increases with temperature.
4
Q
What are the three principles of the atmosphere?
A
Expansion, compression, mobility.
5
Q
What is expansion in the atmosphere?
A
As air rises, it expands and cools
6
Q
What is compression in the atmosphere?
A
Sinking air contracts and is heated.
7
Q
What is gas law?
A
Cold air is more dense and tends to sink.
8
Q
What is dew point?
A
The temperature at a given pressure to which air must be cooled to cause saturation (the state of the atmosphere in which air contains the maximum amount of water vapor that it can hold at a specific temperature and air pressure).
9
Q
What happens when the dew point and temperature are the same?
A
The evaporation of water ceases/stops.
10
Q
What is the difference between the temperature and the dew point called?
A
The spread.
11
Q
What does the spread provide?
A
An indication of how close the air is to saturation (i.e. the temperatures being the same would indicate fog).
12
Q
What is relative humidity?
A
Expresses the water vapour content in the air in percent (60%; the air is 60% saturated).
13
Q
What happens at 100% relative humidity?
A
Air is completely saturated and water vapour will condense to water droplets to form cloud or fog.
14
Q
What are the divisions of the atmosphere in order?
A
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere
15
Q
What range of altitude does the troposphere cover?
A
from surface to 28,000ft over poles, and over 54,000ft over the equator.
16
Q
Which division of the atmosphere does the weather mostly occur?
A
Troposphere.
17
Q
What is true about the atmosphere in terms of pressure, temperature and density?
A
Pressure, temperature and density all decrease with altitude.
18
Q
What is the top of the troposphere called?
A
The Tropopause.
19
Q
What temperature is the tropopause at?
A
-56°C.
20
Q
What temperature is the stratosphere?
A
Remains constant in lower portion 56°C.
21
Q
At what height does the mesosphere go to?
A
275,000ft.
22
Q
What happens to temperature through the mesosphere?
A
The point at which the temperature begins to increase called Mesopause.
23
Q
What temperature range is the thermosphere in?
A
Increases to the 1000’s of degrees.
24
Q
What occurs in the thermosphere?
A
The aurora (Northern Lights) occur in the layer.
25
What is solar radiation?
Energy emitted from sun as "short wave" ultraviolet (UV) radiation.
26
What percent of UV rays are absorbed by the ozone layer?
Approximately 19%.
27
What percent of UV rays is reflected back into space by the atmosphere?
6%.
28
What percent of UV rays is reflected back into space by cloud tops?
20%.
29
What percent of UV rays is reflected back into space by the earth's surface?
4%.
30
What percent of UV rays are absorbed by the earth's surface?
51%.
31
What are the 6 heating processes?
- Conduction
- Convection
- Turbulent mixing
- Advection
- Compression
- Release of latent heat
32
What is conduction?
Heating through contact, air is poor conductor, so limited in effect without other distribution processes
33
What is the equation for heating through contact (conduction)?
Warm ground + cool air + time = cooler ground + warmer air
34
What is convection (heating)?
Air that is warmed becomes less dense (gas law) and tends to rise.
35
What is turbulent mixing?
Friction causes eddies to form as air moves over surfaces (tall built up areas).
36
What is advection?
Horizontal movement of air masses.
37
If an air mass travels over a warm surface, what happens?
Air mass will be warmed; advection.
38
What is compression?
Descending (subsiding) air increases in pressure, in turn increasing temperature.
39
Where can compression occur?
Along ridges of high pressure or mountain ranges.
40
What is adiabatic heating?
When air descends in altitude it COMPRESSES and heats its adiabatic lapse rate.
41
What is adiabatic cooling?
When air rises in altitude it EXPANDS and cools at its adiabatic lapse rate.
42
What is lapse rate?
the rate at which an air warms or cools in response to altitude (pressure) changes.
43
What are the 7 cooling processes?
- Expansion
- Orographic & Upslope lift
- Frontal lift
- Mechanical turbulence
- Convection
- Convergence
- Advection & evaporation
44
What is expansion cooling?
Rising air decreases in temperature.
45
What is orographic & upslope lift?
The result of air flowing over topographical features that cause air to rise (warm body of water).
46
What is frontal lift?
Expansion cooling occurs when warm air is forced up along a frontal surface.
47
What is a cold front?
Advancing cold air displaces warmer air, causing it to rise quickly.
48
What is a warm front?
Advancing air cannot displace the cold air, so warm air gradually rises up and over the cold air.
49
What is mechanical turbulence?
Results from wind flowing over or around irregular terrain (buildings).
50
What is convection (cooling)?
Rising air cools according to the appropriate lapse rate.
51
What is convergence?
Air at the center of a low pressure rises, causing cooling.
52
What is advection?
And air mass moving over a cool surface will cause cooling of the air mass.
53
What is atmospheric stability?
Refers to the resistance to vertical movements of air parcels.
54
What would a steep lapse rate define?
Temperature decreases rapidly with altitude, this implies unstable air.
55
What would a shallow lapse rate define?
Temperature decreases little with altitude, this implies more stable air.
56
What are the 5 pressure terminologies?
- Low
- High
- Trough
- Ridge
- Col
57
What is a low pressure area?
Known a a depression, pressure is lower than the pressure that surrounds it; airflow is counter-clockwise).
58
What is a high pressure area?
Typically larger than low pressure areas, airflow is clockwise.
59
How can you remember to decipher between a low and a high pressure area?
The clock is higher than the counter.
60
What is a trough?
Line of low pressure extending outwards from a low pressure area.
61
What does a trough produce?
Produces convergence resulting in cooling and low ceilings.
62
What is a ridge?
A line of high pressure extending outwards from a high pressure area.
63
What does a ridge produce?
Produces subsidence resulting in compression heating.
64
What is a Col?
A neutral area that exist between two high and low pressures.
65
What happens to your altimeter when traveling from a high to low pressure area?
Altimeter will read high if you fly into a lower pressure area. (High to low, lookout below)
66
What happens to your altimeter when traveling from a low to high pressure area?
Altimeter will read low if you fly into a lower pressure area.
67
What are isobars?
Lines joining places of equal barometric pressure.
68
How far are isobars spread out?
4 hectopascals apart.
69
What is a pressure gradient force (PGF)?
Air moving from high to low pressure.
70
How can we read a PGF to understand the intensity of it?
If the gradient forces are closer together, the stronger it is, which equals strong winds.
71
What is coriolis force?
Air moving from high to low does not flow directly from one to the other, the earth rotating underneath creates a deflection to the right.
72
What is Buy Ballot's law?
If you stand with your back to the wind, in the Northern hemisphere, low pressure will be on your left.
73
When does geostrophic wind occur?
Occurs when pressure gradient force equals coriolis force.
74
What is the sea breeze cycle?
Land (warmer) gives off latent heat and rises, moves over water (cool), which pushes cool air off the water towards land (warmer).
75
What is the land breeze cycle?
Water (warmer), rises into sky, moves over land, cools and falls back down to land (cooler).
76
What is a anabatic wind?
Upslope winds driven by warmer surface temperatures on a mountain slope than the surrounding air column.
77
What is a katabatic wind?
Downslope winds created when the mountain surface is colder than the surrounding air and creates a down slope wind.
78
What are the four causes of turbulence?
- Convective
- Mechanical
- Mountain waves
- Wind shear
79
What is the change in temperature every 1000ft?
5°C.
80
How does wind flow through isobars?
Wind flows across the isobars toward lower pressure.
81
What is convective turbulence?
Hot air rising quickly and creates unstable air to fly trough.
82
What are the four cloud families?
- High
- Middle
- Low
- Clouds of vertical displacement
83
What are the three main high clouds?
- Cirrus (CI)
- Cirrostratus (CS)
- Cirocumulus (CC)
84
What are the main medium clouds?
- Altostratus (AS)
- Altocumulus (AC)
Secondary:
- Altocumulus Castellanus (ACC)
85
What are the main low clouds?
- Stratus (ST)
- Nimbostratus (NS)
- Cumulus (CU)
- Stratocumulus (SC)
Secondary:
- Stratus Fractus (SF)
- Cumulus Fractus (CF)
86
What are the main clouds of vertical displacement?
- Cumulus (CU)
- Cumulonimbus (CB)
- Towering Cumulus (TCU)
87
What is the range for high clouds?
Bases range from 20,000' to 45,000'.
88
What is the range for middle clouds?
Bases between 6,500' to 20,000'.
89
What is the range for low clouds?
Surface to 6,500'.
90
What is a macroburst?
Downburst at least 2.5nm diameter, lasting 5 to 20 minutes.
91
What is a mircoburst?
Downburst smaller size than macroburst.
92
What happens to pressure when a cold front passes?
The pressure decreases until it bottoms out. Then it begins to rise rapidly after it passes.
93
What are the clouds of vertical displacement?
Cumulus, Cumulonimbus, Towereing Cumulonimbus (CU, CB, TCU).
94
What happens to winds when you climb?
You veer and wind increase (veer is clockwise).
95
What happens to winds when you descend?
You back and wind decrease (back is counter-clockwise).
96
What type of cloud is associated with mountain waves?
Lenticular clouds can form (cap clouds).
97
What is the most important factor to weather?
Water vapour.
98
What kind of fog is associated with a front?
Frontal fog.
99
What is the altimeter measured in inches of?
Mercury.
100
What is the minimum ceiling and visibility in VFR?
3SM of visibility, 500ft fron cloud ceiling. (1,500ft ceiling, from circuit altitude)
101
What type of cloud forms after a cold front passes where there is steady participation?
Cumulus or Cumulonimbus. (C or CB).
102
What does it mean when a forecast is spoken and not written?
```
Spoken = MAGNETIC
Written = TRUE
```
103
What type of activity may occur at a SIGMET?
Severe turbulence, icing, wind shear, thunderstorms.
104
How many octaves are covered at few?
1/8.
105
How many octaves are covered at scattered?
4/8.
106
How many octaves are covered at broken?
7/8/
107
How many octaves are covered at overcast?
8/8.
108
What type of surface on an aircraft would have the highest "catch" rate of ice?
A thin wing that flies at a high speed.
109
What are the 4 air masses that affect Canada?
- Maritime polar
- Continental polar
- Arctic
110
What could type is associated with continuous participation?
Nimbostratus clouds (NS).
111
What are the three stages of a thunderstorm?
Cumulus stage, mature stage, dissipating stage.
112
What is the minimum wind speed reported on a GFA?
20kts.
113
What is the difference between clear and rime ice?
Rime ice is lighter than clear ice, rime ice freezes on impact; while clear ice slowly builds up.
114
The three stages of a thunderstorm development, the DISSIPATING is dominantly:
Downdrafts.
115
When approaching an active warm frontal from a cold air masses, the clouds would be in what order?
From high to low, the frontal fog.
116
If the surface temperature is 12C, and the dewpoint is 5C, find the cloud base and freezing level?
Cloud base 2,800ft, freezing level at 6,133ft.
117
In regions of mountain wave activity, turbulence is most significant:
Between the ground and the rotor clouds.
118
What are the high clouds?
Cirrus (C), Cirrocumulus (CC), Cirostratus (CS).
119
What are the medium clouds?
Altocumulus (AC), Altostratus (ACC).
120
What are the multi-level cloud clouds?
Nimbostratus (NB), Cumulonimbus (CB).
121
What are the low-level cloud types?
Stratocumulus (SC), Stratus (S).
