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WorksheetsMet 1 Clouds/Precipitation/Atmosphere/Thermodynamics
Total questions: 84
Worksheet time: 1hrs 6mins
A given mass of air is saturated with water vapour (no condensed water). If temperature increases:
The amount of water vapour remains constant
Relative humidity remains constant
The amount of water vapour decreases
Relative humidity increases
The maximum amount of water vapour that the air can contain depends on the:
Air temperature
Stability of the air
Relative humidity
Dew point
Which of the following statements is true regarding moderate to severe airframe icing?
It is unlikely to occur in nimbostratus cloud
It will not occur in clear-sky conditions
It will occur in the anvil part of the cumulonimbus cloud
It always occurs in altostratus cloud
Which of the following is the definition of relative humidity?
Ratio between water vapour pressure and atmospheric pressure x 100
Ratio between the amount of water vapour (g) and the amount of air (kg) x 100
Ratio between air temperature and dew point temperature x 100
Ratio between the actual mixing ratio and the saturation mixing ratio x 100
Relative humidity depends on:
Temperature of the air only
Moisture content of the air only
Moisture content and temperature of the air
Moisture content and pressure of the air
Relative humidity:
Is higher in warm air than in cool air
Decreases if the air is cooled whilst maintaining the vapour pressure constant
Is higher in cool air than in warm air
Increases if the air is cooled whilst maintaining the vapour pressure constant
Absolute instability in the atmosphere will occur when the environmental lapse rate is:
Less than saturated adiabatic lapse rate
Less than both saturated adiabatic lapse rate and dry adiabatic lapse rate
Greater than both saturated adiabatic lapse rate and dry adiabatic lapse rate
Greater than saturated adiabatic lapse rate but less than dry adiabatic lapse rate
A layer can be:
Stable for unsaturated air and unstable for saturated air
Stable for saturated air and unstable for unsaturated air
Unstable for unsaturated air and conditionally unstable
Unstable for unsaturated air and neutral for saturated air
A parcel of unsaturated air is forced to rise through an isothermal layer. So long as it remains unsaturated, the temperature of the parcel
Decreases 0.65°C per 100 m
Remains constant
Decreases 1°C per 100 m
Becomes equal to the temperature of the isothermal layer
Rising air cools because:
It contracts
Surrounding air is cooler at higher levels
It expands
It becomes more moist
Consider a parcel of air being forced upwards in the atmosphere. The lapse rate of the surrounding air is less than the saturated adiabatic lapse rate. After the initial force is no longer effective, the parcel of air
Will become conditionally unstable.
Will tend to remain at the new altitude.
Will tend to ascend further.
Will tend to descend to its original altitude.
Which of the following statements concerning the lifting of a parcel of air is correct?
Unsaturated parcels cool at a rate of 0.65°C per 100m
Unsaturated parcels cool less rapidly than saturated parcels
Unsaturated parcels cool more rapidly than saturated parcels
Saturated parcels always cool at a rate of 0.65°C per 100m
A parcel of unsaturated air is lifted to just below the condensation level and then returned to its original level. What is the final temperature of the parcel of air?
The same as the starting temperature.
Lower than the starting temperature.
Higher than the starting temperature.
It depends upon the QFE.
A layer in which the temperature decreases with 1°C per 100m increasing altitude is
Absolutely unstable
Conditionally unstable
Absolutely stable
Neutral for dry air
The value of the saturated adiabatic lapse rate is closest to that of the dry adiabatic lapse rate in:
Freezing fog
Cirrus
Stratus
Cumulus
Radiation fog most frequently occurs in:
High pressure systems over sea.
Low pressure systems over land.
Low pressure systems over sea.
High pressure systems over land.
What is the main composition of clouds classified as "high level clouds"?
Water droplets.
Supercooled water droplets.
Water vapour.
Ice crystals.
Which of the following clouds may extend into more than one level?
Cirrocumulus
Stratus
Cumulus congestus
Altocumulus
Which of the following clouds may extend into more than one layer?
Stratus.
Altocumulus.
Cirrus
Nimbostratus.
Which of the following cloud genera may extend over the low, middle and high cloud levels?
Cb
St
Ci
Ac
Which of the following clouds represents the most stable air mass?
Altocumulus lenticularis.
Altocumulus castellanus.
Towering cumulus.
Cumulonimbus.
Freezing fog exists if fog droplets:
Are frozen
Freeze when temperature falls below zero
Are supercooled
Are freezing very rapidly
Which cloud type (genus) is described by the following definition?
"Detached clouds in the form of white, delicate filaments or white or mostly white patches or narrow bands. These clouds have fibrous (hair-like) appearance, or a silky sheen, or both."
Altostratus
Cirrus
Stratus
Cirrostratus
Which of the following types of clouds are evidence of unstable air conditions?
St, Cs.
Cu, Cb.
Sc, Ns
Ci, Sc
Which of the following clouds are classified as medium level clouds in temperate regions?
Ci, Cc
Sc, Ns
Cs, St.
As, Ac.
Which of the following is most likely to lead to the formation of radiation fog?
Cold air passing over warm ground
Dry, warm air passing over warm ground
Heat loss from the ground on clear nights
The passage of fronts
In what conditions does radiation fog form:
2-8kts
Calm conditions only
20-30kt winds
12-20kt winds
Frontal fog can be formed by:
Due to evaporation of water at the surface
When there is adiabatic cooling and the air becomes saturated
When the air becomes saturated due to evaporation of precipitation and water vapour condenses
Due to cooling by night
When the temperature and dew point are less than one degree apart the weather conditions are most likely to be
High scattered clouds
Unlimited visibility
Clear and cool
Fog or low cloud
The morning following a clear, calm night when the temperature has dropped to the dew point, is likely to produce
Radiation fog
A cold front
Advection fog
Good clear weather
A plain in Western Europe with an average elevation of 500 m (1600 ft) above sea level is covered with a uniform AC layer of cloud during the summer months. At what height above the ground is the base of this cloud to be expected?
15000 - 25000 ft
100 - 1500 ft
7000 - 15000 ft
1500 - 7000 ft
Which one of the displayed cloud forms is representative of a cumulus?
1
3
4
2
What is a characteristic phenomenon for a stable atmosphere?
Many vertical currents.
Weak wind
Stratified clouds.
No precipitation.
About ten identical clouds are in the sky, well isolated from one another, dense, with well defined contours, developing vertically in a cauliflower shape. The side of these clouds lit by the sun is bright white. Their base, relatively dark, is essentially horizontal and at FL 30, and their tops at FL 150. These clouds are:
Stratocumulus
Towering Cumulus
Broken Cumulus humilis
Altocumulus castellanus
After a clear night cumuliform clouds are formed in the morning. Why can the base of these clouds become higher during the day?
Because the surface temperature increases.
The wind speed is increasing, because the cold air mass changes into a warm air mass.
Because the stability increases
Because the difference between the temperature and the dew point temperature at the initial condensation level becomes smaller.
As a result of diurnal variation radiation fog is lifted and a cloud cover is formed. Which statement is true?
Layers of altocumulus will develop caused by increasing wind speed.
Low stratus will develop caused by radiation in combination with low geostrophic wind speed.
Stratocumulus will develop caused by insolation.
Low stratus will develop caused by increasing wind speed.
Which of the following are medium level clouds ?
Cirrocumulus and cirrostratus
All convective clouds
Cumulonimbus
Altostratus and altocumulus
The presence of altocumulus castellanus indicates:
Subsidence in a large part of the troposphere
Strong convection at low height
Stability in the higher troposphere
Instability in the middle troposphere
In towering cumulus clouds
Strong updraughts occur and the temperature in the cloud is lower than in the surrounding air at the same height
Strong updraughts occur and the temperature in the cloud is higher than in the surrounding air at the same height
Weak vertical air motion exists and the temperature in the cloud is higher than in the surrounding air at the same height
Weak vertical air motion exists and the temperature in the cloud is lower than in the surrounding air at the same height
Which of the following circumstances most favours the development of frontal fog?
Advection of very cold air over much warmer sea
Increase of the relative humidity by evaporation of rain drops
Nocturnal radiation
Absolutely unstable air
Which of the following cloud types is a medium level cloud?
St
As
Sc
Cs
When fog is reported, the visibility is below
3 km
0.8 km
1 km
1.5 km
What is the average vertical extent of radiation fog?
500 ft
2000ft
3000ft
1000ft
In relation to the total weight of the atmosphere, the weight of the atmosphere between mean sea level and a height of 5500 m is
0.99
0.01
0.5
0.25
You are flying at FL 200. Outside air temperature is -40°C, and the pressure at sea level is 1033 hPa. What is the true altitude?
20630 ft
18290 ft
19310 ft
21770 ft
A temperature inversion indicates a state of the atmosphere which is
Absolutely unstable
Conditionally unstable.
Absolutely stable
Indifferent
What is the tropopause?
The boundary between the troposphere and the stratosphere
The layer between the troposphere and the stratosphere
Upper boundary of CAT
Where temperature increases with height
Which of the following conditions would cause the altimeter to indicate a lower altitude than that actually flown?
Air temperature higher than standard
Pressure altitude the same as indicated altitude.
Air temperature lower than standard.
Atmospheric pressure lower than standard
The average height of the tropopause at 50°N is about:
8 km
14 km
16 km
11 km
If the QNH at Locarno (200 metres above sea level) is 1015 hPa, what is the approximate QFE?
990 hpa
995 hpa
1005 hpa
1000 hpa
A parcel of air has a temperature of 15 degrees C and a dew point of 10 degrees C. What is its relative humidity, approximately?
75%
50%
95%
65%
What is, approximately, the temperature at 20000 ft in the ICAO Standard Atmosphere?
-30°c
-25°c
-20°c
-15°c
An aircraft is flying over the sea at FL 90; the true altitude is 9100 feet; local QNH is unknown. What assumption, if any, can be made about the air mass in which the aircraft is flying?
Its average temperature is the same as ISA
It is warmer than ISA
There is insufficient information to make any assumption
It is colder than ISA
An aircraft lands at an airport (airport elevation 1240 ft, QNH 1008 hPa). The altimeter is set to 1013 hPa. The altimeter will indicate:
1375 ft
1105 ft
1280 ft
1200 ft
An aircraft flying at FL 100 from Marseille (QNH 1012 hPa) to Palma de Mallorca (QNH 1006 hPa) experiences no change to true altitude. The reason for this is that:
The air over Palma de Mallorca is colder than that over Marseille
One of the two QNH values may be incorrect
The air over Palma de Mallorca is warmer than that over Marseille
The altimeters are erroneous, and need to be tested
Which statement concerning the tropopause is correct?
The layer just above the tropopause is absolutely stable
In the ICAO standard atmosphere the tropopause lies higher over the poles than over the equator
Above the tropopause no clear air turbulence occurs
The temperature at the tropopause is approximately -80°C over the poles and approximately -40°C over the equator
At which pressure and temperature conditions may you safely assume that the minimum usable flight level at least lies at the same height, as the minimum safe altitude?
At a temperature less than or equal to that of the ISA and where the QNH is less than 1013.25 hpa
In a very cold area with a QNH of 1015 hpa
In a cold low pressure region
At a temperature greater than or equal to that of the ISA and where the QNH is greater than or equal to 1013.25 hpa
An aircraft flies at flight level 40. Elevation of the aerodrome: 990 ft; QNH 976 hPa. The tower clears the pilot to fly at 3000 ft QNH. Which of the following statements is correct?
The aircraft has to descend about 2000 ft.
Only a small change of altitude is necessary.
The aircraft has to climb about 1000 ft.
The aircraft has to descend about 1000 ft.
Pressure altitude is obtained by:
Setting the altimeter to standard sea level pressure.
Setting the altimeter to a station pressure which has been corrected to sea level.
Correcting the altimeter for temperature deviation from isa
Setting the altimeter to qff pressure.
Which statement is true concerning the tropopause from the equator to the poles?
The tropopause increases, the tropopause temperature increases
The tropopause decreases, the tropopause temperature decreases
The tropopause increases, the tropopause temperature decreases
The tropopause decreases, the tropopause temperature increases
QNH is defined as
QFE reduced to MSL using the values of the standard atmosphere
QFE reduced to MSL using the values of the actual atmosphere
Pressure at MSL in the actual atmosphere
Pressure at MSL in the standard atmosphere
In order to calculate QFE from QNH, which of the following must be known?
Temperature at the airfield.
Elevation and the temperature at the airfield.
Elevation of the airfield.
Elevation of the airfield and the temperature at MSL.
The mean height of the tropical tropopause is:
49000 ft
54000 ft
59000 ft
44000 ft
An aircraft flying at FL 45 (OAT 6°C) obtains a reading of 1860 ft on its radio altimeter (ground elevation 3090 ft). What is the value of the QNH, to the nearest hPa, at that point?
1042
1013
1030
996
In still air the temperature decreases at an average of 1.2°C per 100 m increase in altitude. This temperature change is called:
Isa lapse rate in the troposphere
Dry adiabatic lapse rate
Saturated adiabatic lapse rate
Environmental lapse rate
What is meant by the term "altitude"?
The vertical distance of a level or a point measured from mean sea level.
The vertical distance of a level or a point measured from the earth's surface.
The vertical distance of a level or a point measured from the aerodrome reference point.
Altimeter indication when altimeter subscale is set to present QFE.
In the ICAO standard atmosphere, which of the following alternatives indicates the correct vertical temperature distribution in the lowest 11 km?
15.2°C at mean sea level, decreasing at 0.65°C per 100 metres.
15°C at mean sea level, decreasing at 0.65°C per 100 metres.
15°C at mean sea level, decreasing at 0.65°C per 100 feet.
13°C at mean sea level, decreasing at 2°C per 1000 feet.
When flying in mountainous terrain and assuming ISA temperatures and strong winds, which of the following is correct?
In case of venturi effect, the actual altitude of the aircraft is lower than the indicated altitude.
In case of combined effect of surface friction and adiabatic compression of the air, the dynamic pressure is lower than indicated by the altimeter.
In case of venturi effect, the indicated altitude of the aircraft is lower than the actual altitude.
In case of adiabatic compression of the air, the temperature is lower than indicated.
A vertical spacing of 1000 ft is the standard required separation between two FL. Under conditions of cold air advection (ISA -15°C), what would the true vertical separation be?
More than 1000 ft
Less than 1000 ft
It remains 1000 ft
Without QNH information, it can not be determined
If the QFE at Locarno (200 metres above sea level) is 1000 hPa, what is the approximate QNH?
985 hpa
990 hpa
1035 hpa
1025 hpa
On average, going from the equator to the North Pole, the altitude of the tropopause:
Decreases and its temperature decreases
Increases and its temperature decreases
Decreases and its temperature increases
Increases and its temperature increases
The processes and/or effects which cause clouds to release precipitation are
Bergeron-Findeisen process and convection effect.
Convection effect and advection effect.
Coalescence process and Bergeron-Findeisen process.
Advection effect and coalescence process.
What is the size of the droplets found in drizzle?
2mm
0.5mm
1mm
4mm
What type of clouds are associated with snow showers?
Cumulus and altostratus
Cumulus and cumulonimbuS
Nimbostratus
Altostratus and stratus
With what type of cloud is "GR" precipitation most commonly associated?
St
Cc
Cb
As
What type of clouds are associated with rain showers?
Towering cumulus and cumulonimbus
Altostratus and stratus
Nimbostratus
Towering cumulus and altostratus
Large hail stones
Only occur in frontal thunderstorms
Are entirely composed of clear ice
Only occur in thunderstorms of mid-latitudes
Are typically associated with severe thunderstorms
How does freezing rain develop?
Through melting of ice crystals
Through melting of snow grains
Snow falls through a layer where temperatures are above 0°C
Rain falls through a layer where temperatures are below 0°C
With what type of cloud is "DZ" precipitation most commonly associated?
Cc
Cb
St
Cu
The presence of ice pellets at the surface is evidence that:
There are thunderstorms in the area
A warm front has passed
A cold front has passed
Freezing rain occurs at a higher altitude
With which of the following types of cloud is "+RA" precipitation most commonly associated?
Sc
Ac
Ns
St
In the middle of the eye of a hurricane the wind speed is:
Lower than 63 knots and the air is descending
Higher than 63 knots and the air is descending
Lower than 63 knots and the air is ascending
Higher than 63 knots and the air is ascending
In January an extended high pressure area is normally observed over:
South America
Siberia
Central Europe
Southern Africa
Considering the North Atlantic region between 30°N and 65°N and the adjacent land areas during mid-summer, the predominant pressure systems are:
Weak low over NE Canada and Scandinavian high
Azores low and Icelandic high
Scandinavian high and Azores high
Azores high and weak low over NE Canada
