AFT MET Flashcards
The troposphere:
A. Is a section of the atmosphere above the tropopause where there is little or no change in temperature with height
B. Is 8-18km above the earths surface where a marked change in temperature lapse rate is apparent
C. Contains most of the water vapour of the atmosphere and the temperature generally decreases with height
D. Is the boundary between the tropopause and stratopause
Contains most of the water vapour of the atmosphere and the temperature generally decreases with height
With increasing altitude in the stratosphere, temperature:
A. Increases
B. Remains the same
C. Decreases
D. Is isothermal
Increases
*In the lower parts of the stratosphere, temp is constant which is called isothermal and then increases with altitude
The tropopause is:
A. A region in the upper stratosphere where the temperature decreases with height
B. A region 8-18km above the earths surface at which a marked change in temperature lapse rate is apparent
C. That portion of the earths atmosphere in which weather occurs
D. A level within 3000ft of the ground at which a marked change of lapse rate is indicated on cold clear mornings
A region 8-18km above the earths surface at which a marked change in temperature lapse rate is apparent
In ISA, from MSL to the tropopause, the decrease of temperature with height is approximately:
A. 1C/1000ft
B. 1.5C/1000ft
C. 2C/1000ft
D. 3C/1000ft
2C/1000ft
*Up to 36,090ft where the tropopause starts
In ISA, the tropopause is found at:
A. The equator
B. 0HPA pressure
C. 36,090ft
D. 8km above the poles
36,090ft
One of the major differences between the troposphere and stratosphere is that the stratosphere:
A. always has a higher temperature and humidity than the troposphere
B. has almost no clouds
C. always has a lower temperature and humidity than the tropopause
D. always has a greater wind velocity than the troposphere
has almost no clouds
*Stratosphere has the isothermal layer and then temp increases with height, has almost no clouds
From the earths surface, the vertical structure:
A. tropopause, stratosphere, troposphere
B. stratosphere, troposphere, tropopause
C. troposphere, stratosphere, tropopause
D. troposphere, tropopause, stratosphere
Troposphere, tropopause, stratosphere
*stratopause, mesosphere, mesopause,
The lapse rate in the stratosphere is due to:
A. nearness of the sun
B. lack of air
C. radiation from the earth
D. presence of heat absorbing ozone
presence of heat absorbing ozone
*Ozone absorbs the UV coming from the sun
The section of the atmosphere where most weather occurs is:
A. Troposphere
B. Stratosphere
C. Stratopause
D. Friction layer
Troposphere
*Friction layer is surface-3000ft
The temperature at the base of the stratosphere is lowest over:
A. equator
B. 30 degrees latitude
C. 60 degrees latitude
D. the poles
Equator
*Like a flattened circle around the earth, 26,500ft and -40 over poles, 56,500ft and -70 over equator
Normally the diurnal range of the temperature is greatest at:
A. a coastal location
B. a mid-ocean location
C. an inland location
D. a location with overcast cloud
an inland location
*Diurnal means 24hr or daily variation - range is greatest over a desert
The diurnal variation of temperature is:
A. temperature changes due to seasonal changes
B. temperature pattern over a 24hr period
C. greatest during overcast periods
D. least just after sunrise
temperature pattern over a 24hr period
*Durinal Variation is the amount that temp changes - most over dry inland,
Least over high humidity
Least with overcast because it traps the heat
Solar radiation passing through the atmosphere is:
A. absorbed
B. scattered
C. reflected
D. all of the above
all of the above
On ISA day, you would expect the temperature at an elevation of 4000ft AMSL to be:
A. +15C
B. +23C
C. +11C
D. +7C
+7C
*ISA is +15 at Sea Level, -2C/1000ft
The sea level temp in standard atmosphere is:
A. 20.92C
B. 1013 HPA
C. +15C
D. +30C
+15C
The change of temperature for an increase in altitude known as:
A. lapse rate
B. temperature inversion
C. convection
D. advection
lapse rate
The primary cause of weather is:
A. curvature of the earth
B. the seasons
C. temperature differential
D. rain
temperature differential
A line on the weather chart joining places having the same temperature is called an:
A. isotherm
B. isobar
C. isotach
D. inversion
Isotherm
*isobar = lines of equal pressure
Radiant energy arriving from the sun is termed:
A. photochemical energy
B. insolation
C. insulation
D. light waves
insolation
Our weather is due to the atmosphere being heated mainly by:
A. radiation from the sun
B. insolation from the sun
C. radiation from the earth
D. advection
radiation from the earth
In the standard atmosphere at MSL, temperature, pressure and lapse rate equal respectively:
A. -15C / 1013 HPA / -3C/1000ft
B. +15C / 1013 HPA / 1.5C/1000ft
C. 0C / 1310 HPA / 2C/1000ft
D. +15C / 1013 HPA / 2C/1000ft
+15C / 1013 HPA / 2C/1000ft
A line on a weather map joining lines of equal pressure is called:
A. isotherm
B. contour
C. isogonal
D. isobar
isobar
*isotherm is a line of equal temperature
Atmospheric pressure is reported and recorded on weather charts in terms of:
A. inches of mercury
B. centimetres of mercury
C. millimetres of mercury
D. millibars or hectopascals
millibars or hectopascals
The pressure gradient is:
A. rate of change of pressure with height and is approx. 30ft/HPA
B. generating force of the gradient wind, which then blows along the pressure gradient
C. change of pressure with distance, measured horizontally at right angles to the isobars
D. rate of change of pressure with time and is therefore related to the acceleration of air particles
change of pressure with distance, measured horizontally at right angles to the isobars
The diurnal variation of pressure is:
A. the daily variation of pressure independent of that due to the movement and development ion pressure systems
B. the algebraic sum of the pressure variation over a given period of the day
C. the change of pressure over 24hrs and is measured at 9am each day
D. usually the indication of movement of a nearby system
the daily variation of pressure independent of that due to the movement and development ion pressure systems
Below 5000ft, pressure drops by 1HPA with an ascent of approx:
A. 60ft
B. 40ft
C. 30ft
D. 15ft
30ft
Pressure may be defined as:
A. mass per unit area
B. force per unit area
C. mass per unit volume
D. force per unit volume
force per unit area
The density of air is:
A. directly proportional to pressure and inversely proportional to temperature
B. inversely proportional to pressure and directly proportional to temperature
C. directly proportional to both pressure and temperature
D. inversely proportional to both pressure and temperature
directly proportional to pressure and inversely proportional to temperature
*Directly proportional to pressure
Inversely proportional to temperature and humidity
The sea level pressure in ISA in Australia is:
A. 1013.2 HPA
B. 29.92 in Hg
C. 40 kt
D. +15C
1013.2 HPA
The rate at which atmospheric pressure decreases with altitude in a column of air:
A. is constant regardless of temperature
B. decreases and is dependant on the mean temperature of the column
C. decreases and is not affected by the mean temperature of the column
D. increases and depends on the mean temperature of the column
decreases and is dependant on the mean temperature of the column
Before takeoff for a cross country flight planned to cruise at FL110, the altimeter sub scale should be set to:
A. QFE
B. 1013.2 HPA
C. local QNH if known
D. area QNH
local QNH if known
*question asks before takeoff so 1013 is set through transition
*QFE is station level pressure, if you set QFE on subscale, the main scale will indicate height above or below the reference pressure point - QFE can be found by setting 0ft on the mainscale
What effect does density have on aircraft performance:
A. air is thinner at altitude therefore performance is better
B. performance is better when the density is lower
C. good performance occurs when density is high
D. higher density, poorer performance
good performance occurs when density is high
If the altimeter sub scale is set to 1013, the altimeter will read:
A. pressure height
B. density height
C. altitude
D. elevation
pressure height
While in level flight with the QNH correctly set, the altimeter indicates the aircrafts:
A. precise altitude above MSL
B. actual height above the terrain
C. approximate height above MSL
D. altitude above the departure aerodrome
approximate height above MSL
Aerodrome level pressure is:
A. QFF
B. QNH
C. QNE
D. QFE
QFE
*QNH = area QNH is predicted average sea level pressure for 3hr periods
QFF = meteorological mean sea level pressure
QFE = station level pressure, mainscale will indicate height above the reference pressure point
While at or below 10,000ft, the altimeter sub scale is to be:
A. QFE
B. 1013.2HPA
C. destination local QNH
D. local QNH of a point within 100nm of the aircraft or area QNH
local QNH of a point within 100nm of the aircraft or area QNH
The accepted relationship between pressure in hectopascals and height in the lower layers of the atmosphere is:
A. 30HPA/1ft
B. 1HPA/30 in Hg
C. 1HPA/30ft
D. 1013HPA/36,090ft
1HPA/30ft
What is the relationship between pressure and altitude:
A. increase in altitude results in a decrease in pressure
B. aircraft climbing will experience increased pressure
C. high pressure is experienced at high altitude
D. at high altitudes the air is thin therefore pressure is high
increase in altitude results in a decrease in pressure
The QNH altimeter setting is:
A. height AMSL expressed in hectopascals
B. atmospheric pressure exerted on a particular area
C. sub scale setting at which the altimeter indicates airfield elevation on landing
D. sub scale setting at which the altimeter indicates pressure height
sub scale setting at which the altimeter indicates airfield elevation on landing
When flying from an area of high pressure into lower pressure, the altimeter will:
A. overread
B. underread
C. be unaffected
D. give fluctuating readings
overread
The correction applied to station level pressure to obtain the QNH assumes:
A. the density of a column of air extending down to MSL is independent of temperature at station
B. the density height measure at the station is greater than the pressure height
C. the density of a column of air extending down to MSL is dependent on the temperature at station
D. the density height measure at the station is less than the pressure height
the density of a column of air extending down to MSL is independent of temperature at station
The correction applied to station level pressure to obtain MSL pressure (known as QFF) assumes the density of the column of air extending from the station to MSL:
A. is constant and the same as the outside air density at the station
B. increase with a decrease in height and depends on the outside air temperature at the station
C. is constant and independent of the outside air temperature of the station
D. decrease with a decrease in height and is independent of the outside air temperature at the station
increase with a decrease in height and depends on the outside air temperature at the station
When a parcel of air becomes saturated and condensation occurs:
A. all the water vapour changes to liquid state
B. latent heat is absorbed
C. rain will commence
D. latent heat is released
latent heat is released
Relative humidity is:
A. the percentage degree of saturation
B. the ratio of the amount of water vapour to the amount of air in which its contained
C. the ratio of mass of eater to the mass of dry air in which its held
D. unaffected by changes in temperature
the percentage degree of saturation
The dew point is the temperature:
A. indicated by the wet bulb thermometer in a Stevenson screen
B. to which a sample of moist air must be cooled at constant pressure for it to become saturated
C. defined by the following equation, DP temperature/air temperature = RH
D. at the top of a cloud
to which a sample of moist air must be cooled at constant pressure for it to become saturated
When water droplets in the liquid state freeze:
A. the relative humidity decreases
B. latent heat is released
C. latent heat is absorbed
D. hail will commence to fall
latent heat is released
Relative humidity is measured using a:
A. Hydrometer
B. Barometer
C. Altimeter
D. Psychrometer
Psychrometer
A parcel of air has a temperature of +15C and a RH of 80%. A temperature rise of 10C will cause:
A. rain to form
B. RH to decrease
C. RH to increase
D. condensation
RH to decrease
*As temp increases, RH decreases
The water vapour air in saturated air is:
A. visible sometimes
B. visible if the temperature is low enough
C. visible always
D. invisible always
invisible always
When the temperature and dew point are the same:
A. the atmosphere is stable
B. the atmosphere is unstable
C. dew cannot form
D. the RH is 100%
the RH is 100%
The reading of wet and dry bulbs thermometers at met stations serves to calculate:
A. humidity
B. pressure
C. stability
D. minimum temperature
humidity
Relative humidity is the:
A. ratio of the amount of water vapour present to the amount of water vapour that could be held in a sample of air
B. ration of the mass of water vapour to the total mass of the sample of atmosphere in which it is contained
C. ratio of the mass of water vapour to the mass of dry air with which it is associated
D. percentage volume ratio of the water vepour in a sample of air
ratio of the amount of water vapour present to the amount of water vapour that could be held in a sample of air
When the air temperature at a particular level is higher than that existing at a lower level:
A. the pressure will be low
B. the pressure will be high
C. the air is unstable
D. an inversion exists
an inversion exists
*inversion is when temp increases with altitude
Warm air is rising adiabatically above a ploughed field, surface temp +21C. The DP a the cloud base is +3C. The cloud base and freezing level are respectively:
A. 7500ft and 9500ft
B. 9000ft and 11000ft
C. 9000ft and 10500ft
D. 6000ft and 8000ft
6000ft and 8000ft
If the ELR is between 1.5 and 3C the air is:
A. stable
B. unstable
C. neutrally stable
D. stable for dry air and unstable for saturated air
Stable for dry air and unstable for saturated air
*SED
S - SALR
> stable
E - ELR
> unstable
D - DALR
Above the condensation level, the lapse rate of rising air will:
Reduce from the DALR to the SALR
An inversion results in:
Extremely stable conditions above
Warmer temperatures above a colder layer of air indicates:
An inversion
When ELR is greater than DALR, dry air is:
Unstable
*S >stable> E >unstable> D
DALR is
-3/1000ft
When SALR is greater than ELR, saturated air is:
Stable
*S >stable> E >unstable> D
The actual change in temperature for an increase in altitude is known as:
The environmental lapse rate
Warm air is rising adiabatically above a ploughed field, surface temp 21C. The surface dew point is 3. Allowing for dew point lapse rate, the cloud base and freezing level are:
7500ft and 7000ft
The average rate of decrease in temperature per 1000ft is
2C/1000ft
An adiabatic process is:
Where no heat is transferred into or out of the system
A katabatic wind:
Is a downslope flow of cold air
*when clear night says cool the mountain side by conduction
Surface wind around a low pressure system in the Southern Hemisphere flows:
Clockwise and inwards
If the wind direction changes in a clockwise direction, it is said to:
Veer
Coriolis force in the Southern Hemisphere acts:
At right angles to the direction of the wind, causing a deflection to the left
A land breeze is a wind that blows:
From the land to sea during the night
*Sea breeze blows from the sea during the day
Close isobars mean:
Strong winds
A wind caused by uneven heating in coastal regions flows:
From the sea by day and from the land by night
If the forecast is 030T/20, it will blow:
From 030 true
When flying towards a low in the Southern Hemisphere, an aircraft would experience:
Left drift
*Low winds go clockwise and inwards
Low is called a depression/cyclone
Elongated low is a trough
Within the friction layer with increasing height, the wind:
Backs
If you stand with your back to the wind in the Southern Hemisphere, the region of low pressure:
Will be on your right
The friction layer extends up to about:
3000ft
With the passage of a cold front in the Southern Hemisphere:
The wind backs, temperature falls and pressure rises
*A cold front undercuts warm air and forces it to rise
Cold front generates unstable conditions ahead of it
May result in frontal thunderstorms ahead of it
True or false: Warm fronts always lie along ridges and cold fronts always lie along troughs.
False
A cold front usually lies along a:
Trough of low pressure
A cold air mass is characterised by:
Unstable conditions, cumuliform clouds
*Cold fronts = Cu ahead of it
(cold and cumulus both begin with C)
*Think of me being cold, being unstable and unhappy
*When I’m warm, I’m stable
*Warm fronts = stratus and nimbostratus
A defined boundary between 2 air masses is called:
Front
Warm air masses are characterised by:
Stable with hazy conditions
*Warm front is when warm air replaces the cold air by sliding over the top of it
*Warm air is generally stable, causing stratus clouds with rain from nimbostratus
*Approach of a warm front is high level cloud, then mid level cloud then extensive Ns
*Passage of a warm front marked by:
-Back in wind, rise in temp and pressure fall decreasing
A cold front is a zone where:
Cold air is displacing warm air at the surface
*Think of the angry triangle diagram pushing the warm air up
A warm front is a zone where:
Warm air slides over cold air at the surface
*Warm air rises because it’s less dense so it can’t push the cold air up but it can take it over on top of
With the passage of a warm front in the Southern Hemisphere:
The wind backs, temp rises and pressure fall decreases
*Passage of a warm front, temp rises
*Passage of a cold front, temp falls
Following the passage of a warm front, the most likely weather scenario would be:
Nil significant weather
*Heavy rain when the warm front is passing but nothing after it
The approach of a warm front would be indicated by:
High level cloud, followed by mid level cloud and eventually extensive Ns
Frontal thunderstorms would be triggered:
By the passage of a cold front
*Cold fronts have cumulus cloud ahead of them and can develop into TS with the unstable conditions
*After a warm front is nil significant weather
The north west monsoon:
Brings unstable moist air to darwin
*Ie the wet season
The inter tropic convergence zone is a boundary between:
Airstreams operating in the northern and southern hemispheres
The major hazard of a tropical cyclone to an aircraft in flight is:
Severe turbulence
A strong wind across a mountain range will produce:
Strong down currents on the lee side
(Picture a mountain like a slip n slide and the wind is zipping down the lee)
The cyclone season in Australia is:
November to April
You would expect to encounter the most severe turbulence when flying at a height of 3000ft above the ground at a:
Rapidly moving cold front with unstable air
*Cu clouds ahead of a cold front
Potential thunderstorms
The approach of a tropical revolving storm is heralded by:
Falling pressure with increasing wind speed
The most pronounced thermal turbulence is found:
In the afternoon over land
If the air is unstable in the lower layers only, the following conditions could be expected:
Bumpy with cumulus cloud
The characteristics of warm air masses are:
Stable lapse rate and stratiform cloud
*Warm = stable, stratiform ahead of it
Starts high level, then mid level, then extensive Ns with rain
*Nil significant weather after its passed
*After warm front passing:
-Wind backs, temp rises and pressure fall decreases
Cold streams passing over south eastern Australia are usually unstable because:
The surface which they pass over is warmer than the air
The pressure gradient force acts:
At right angles to the isobars, towards the lower pressure
The strength of the pressure gradient force depends most on:
Spacing of the isobars
*Close isobars = strong winds
Coriolis force explains the tendency of wind to:
Turn left in the southern hemisphere
Surface wind when compared to gradient wind flow is found to be:
Veered to the right and slower
*As altitude increases from the ground, the wind backs and increases - no more friction so it can speed up
Compared to the gradient wind flow, the surface wind over land will have:
Veered by 30degrees and slowed by 2/3rds
*Over the sea it will veer but only slow by 1/3rd
The term geostrophic wind refers to the steady flow of wind:
parallel to straight isobars
*when the Coriolis force is balanced by the pressure gradient force it means isobars are straight
*Gradient wind flows parallel to curved isobars
Anticyclonic flow occurs:
About a high in the southern hemisphere
*Cyclone is clockwise, around a low/depression
Cyclonic flow occurs:
Around a low in the southern hemisphere
*Cyclone = low/depression/clockwise
Katabatic wind will tend to reinforce:
A land breeze
The variations in pressure which normally occur with the passage of a cold front are:
Wind backs, temp drops and pressure rises
A Fohn wind is likely to result in:
Lower humidity on the lee side of the mountain at low level
*Also cloud base will be higher on lee side
Lee side surface temps will be higher
Which statement best describes a squall line:
Low cloud moving rapidly in the warm air infront of a cold front
*Cold front has Cu clouds ahead of it which can form TS and squall lines are TS’s
At which latitude would there be the greatest difference between the actual wind and gradient wind at 5000ft
5 degrees S
A statement which best describes a backing wind is:
It changes direction anticlockwise
*Backing is anticlockwise
*Anticlockwise around a high or anti-cyclone
For a katabatic wind to form, there must be:
A surface inversion
*So the cold air can roll down the side of the hill
Squall lines are most often associated with:
Thunderstorms
Surface friction causes:
A decrease in the Coriolis effect
*Because surface friction decreases wind speed
*Coriolis is 0 at the equator and maximum at the poles
*Stronger the wind, stronger the Coriolis deflection
An aircraft heading directly from a high pressure system to a low pressure system will:
Drift towards the left
*Low = clockwise
High = anticlockwise, draw the patterns to picture it
Conditional stability is said to exist when:
When dry air is stable and saturated air is unstable
*The opposite to the norm:
S >stable> E >unstable> D
Which conditions are most likely to produce radiation fog:
Nil cloud and light winds
During what stage of a thunderstorm would lightning be most frequent:
At the mature stage
Where is hail most likely to be encountered in a thunderstorm
Between 10000ft and 30,000ft
In which conditions are thunderstorms most likely:
Latitudinal heating of a fast moving cold moist air stream
Which of the cloud types are most likely to produce Virga
Thin altostratus
*Virga is rain that doesn’t touch the ground
*thin altostratus is rime icing
*thick altostratus could have clear icing
*Ns is continuous rain
Which is most likely to be encountered in nimbostratus:
Heavy continuous rain
*Thin altostratus is virga
*Ns is also orographic cloud and clear ice is present up to 5000ft above the fzl level
The lifting of fog may be caused by:
An increase in wind strength
*To blow it away
The most common way for cumulus cloud to form is:
Rising air being cooled by expansion
Which phenomena in a TS causes low level wind shear at some distance away from the cell:
Downdrafts