MET ATPL Flashcards
The troposphere ?
Contains most of the water vapour of the at atmosphere and and the Temperature usually decreases with height
With increasing Altitude in the stratosphere temperature usually ?
Increases
The tropopause is ?
A region 8km to 18km above the earths surface at which a marked change in temperature lapse is apparent.
ISA decreases from sea level to the tropopause at what rate ?
2 degrees/1000ft
In ISA the tropopause is found at ?
A height of 36090 ft
One major difference between the troposphere and the stratosphere is ?
The stratosphere has almost no clouds.
From the earths surface, the vertical structure of the atmosphere is ?
Troposphere, tropopause, stratosphere
The lapse rate in the stratosphere is due to ?
The presence of the heat absorbing ozone.
Section of the atmosphere in which most roc the weather occurs ?
Troposphere
The temp at the base of the stratosphere is lowest over ?
The equator
The temp in the ISA tropopause is ?
-56 degrees C
Normally the diurnal variation of temp is greatest at ?
An inland location
The diurnal variation of temperature is?
The temperature Pattern over a 24 hour period.
Solar radiation passing through the atmosphere is?
Absorbed scattered and reflected.
On and ISA day you would expect the temperature at an elevation of 4000 feet above MSL to be?
+7 C
The sea level temperature in the standard atmosphere is?
+15°C
The change of temperature for an increase in altitude known as?
The lapse rate
The primary cause of weather is?
Temperature differential.
A line on the weather chart joining places having the same temperature is called ? 
Isotherm
Radiant energy arriving from the sun is termed?
Insolation
Our weather is due to the atmosphere been heated mainly by?
Radiation from the earth.
In the standard atmosphere at mean sealevel, temperature, pressure and lapse rate equal respectively?
+15°C/1013HPA/2°C/1000 feet
A line on a weather chart joining places of equal pressure is called?
And isobar
Atmospheric pressure is reported and recorded on weather charts in terms of?
Millibars or hectopascals
The pressure gradient is the ?
Change of pressure with distance, measured horizontally at right angles to the isobars.
The diurnal variation of pressure is?
The daily variation of pressure independent of that due to the movement and development of pressure systems.
Below 5000 feet pressure drops by 1 HPA with an ascent of approximately?
30 feet
Pressure may be defined as?
Force per unit area.
The density of air?
Is directly proportional to pressure and inversely proportional to temperature.
The sea level pressure in the standard atmosphere is defined in Australia as?
1013.2 HPA
The rate at which atmospheric pressure decreases with altitude in a column of air?
Decreases and is dependent on the main temperature of the column.
Before take off for a cross country flight planned to cruise at flight level 110, the altimeter subscale should be set to?
Local QNH if known or aerodrome elevation
What affect does density have on aircraft performance?
Good performance occurs when density is high.
If the Altimeter subscale setting is 1013HPA the Altimeter will read?
Pressure height
While and level flight with the area QNH correctly set, the altimeter indicates the aircraft?
Approximate height above mean sea level.
Aerodrome level pressure is known as?
QFE
While cruising at or below A100, the altimeter sub scale setting to be used is ?
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?
1 HPA/ 30ft
What is the relationship between pressure and altitude ?
Increase in Altitude result in a decrease in pressure.
The QNH Altimeter setting is the ?
Sub scale setting at which the altimeter indicates airfield elevation on landing.
When flying from an area of high pressure into an area of low pressure the altimeter will ?
Over- read
The correction applied to station level pressure to obtain the QNH assumes?
The density of a column of air extending down to mean sealevel is independent of temperature at station.
The correction applied to station level pressure to obtain meteorological MSL pressure known as QFF assumes the density of a column of air extending from the station to MSL?
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?
Latent heat is released.
Relative humidity is?
The percentage degree of saturation
The dew point is the temperature?
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?
Latent heat is released.
Relative humidity is measured using a?
Psychrometer
A parcel of air has a temperature of 15°C and a relative humidity of 80%. A temperature rise of 10°C will cause?
The relative humidity to decrease.
The water vapour held in saturated air is?
Invisible always
When the temperature and Dewpoint are the same?
Relative humidity is 100%
The reading of wet and dry bulb thermometers at meteorological stations serves to calculate?
Humidity
Relative humidity is the ?
Ratio of the amount of water vapour present to the amount 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?
And inversion exists
Warm air is rising adiabatically above a ploughed field, surface temperature 21°C. The dew point at the cloudbase is 3°C the cloudbase and freezing level respectively are approximately?
6000 feet and 8000 feet
If the ELR is between 1.5 degrees C and 3 degrees C the air is ?
Stable for dry air and unstable for saturated air.
Above the condensation level the lapse rate of rising air will ?
Reduce from the dry adiabatic lapse rate to the smaller saturated adiabatic lapse rate.
An inversion results in ?
Extremely stable conditions above.
No
Hb
Warmer temperatures above a colder layer of air indicates ?
An inversion
When the ELR is greater than the DALR, dry air is ?
Unstable
The dry adiabatic lapse rate is ?
3 degrees C/1000ft
When SALR is greater than the ELR, saturated air is ?
Stable
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 temperature +21 degrees C. The surface dew point is +3 degrees C. Allowing for the dew point lapse rate, the cloud base and freezing level respectively are approximately?
7500ft and 7000ft
The average rate of decrease in temperature per 1000ft of height is approximately?
2 degrees C
An adiabatic process is one ?
In which no heat is transferred into or out of the system.
A met station on the diagram, is located on the leeward side of a coastal range. From the data given, the MSL temperature on the windward side of the range using DALR and SALR is ?
20 degrees
A katabatic wind is ?
Is a downslope flow of cold air.
The surface wind around an area of low pressure in the Southern Hemisphere blows ?
Clockwise and inwards
If the wind direction changes in a clockwise direction it’s said to ?
Veer
The Coriolis force in the Southern Hemisphere acts ?
At right angles to the wind, causing a deflection to the left.
A land breeze is a wind that blows from the ?
Land to the sea during the night
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.
Is the forecast wind is 030/20 kn, it will blow?
From 030 T
When flying towards a low in the southern hemisphere an aircraft will experience?
Left drift.
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?
3000 feet
What’s the passage of a cold front in the southern hemisphere?
The wind Backs, the temperature falls and the pressure rises.
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, Cumuloform clouds.
A defined Boundry between two Air masses is called a?
Front.
Warm air masses are characterised by?
Stable with hazy conditions.
A cold front is a zone where?
Cold air is displacing warm air at the surface.
A warm front is a zone where?
Warm air slides over cold air at the surface.
What’s the passage of a warm front in the southern hemisphere?
The wind Backs, the temperature rises and the pressure fall decreases.
Following the passage of a warm front, the most likely weather scenario would be?
Nil significant weather.
The approach of a warm Front will Be indicated by?
High-level cloud, followed by mid-level cloud and eventually extensive Nimbostratus.
Frontal thunderstorms would be triggered?
By the passage of a cold front.
The north west monsoon?
Brings unstable moist air to Darwin.
The inter Tropic convergent zone is a Boundry between?
Airstreams originating in the northern and southern hemisphere.
The inter Tropic convergent zone is found near?
The equator.
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.
Cyclone season in Australia is from?
November to April
You would expect to encounter the most severe turbulence when flying at a height of 3000 feet above the ground at a?
Rapidly moving cold front with unstable air.
The approach of a tropical revolving storm is Heralded bye?
Falling pressure with increasing wind speed.
The most pronounced thermal turbulence is found?
In the afternoon Overland.
If the air is unstable in the lower layers only, the following conditions could be expected ?
Bumpy with cumulus clouds.
The characteristics of warm in masses are?
Stable laps rate and strata form clouds.
Cold streams passing over south eastern Australia are usually unstable because?
The surface over which they pass is warmer than the air.
Hazard at all levels in a CB is?
Turbulence.
The main hazard pose to an aircraft by air frame icing is?
Reduced aerodynamic efficiency
The type of icing likely to be encounted above the freezing level in strata form cloud is?
Rime ice
Type of icing likely to be experienced just above the freezing level in cumuliform type cloud is?
Clear ice.
The formation of Clear ice requires?
Large droplets and an outside air temperature between 0° and -15°C
The most Severe airframe Icing is found?
Between 0° and -15°C
To hazards posed to an aircraft around a thunderstorm could be?
Turbulence and hail.
The minimum outside air temperature at which clear Airframe icing would be unlikely is?
+ 5°C
When a thunderstorm is in the vicinity of an airport, one hazard preventing aircraft landing and taking off is?
Wind shear
Airframe icing is most likely?
With visible moisture at temperature below freezing
The type of icing likely to be encounted in an orographic cloud when the outside air temperature is -10°C would be?
Clear ice 
The icing experience went flying through rain at temperatures below freezing would be?
Heavy clear
When avoiding thunderstorm, horizontal separation should be at least?
20 nautical miles
While on approach to land, an aircraft encounters abrupt decrease in the headwind component. The initial affect will be?
A decrease in airspeed and an undershoot tendency
The most hazardous form of airframe ice is?
Clear ice
Clear icing in Australia is normally associated with the following clouds?
Large cumulus, Cumulonimbus, Nimbostratus.
Before flight, the pilot noticed a thin white Crystaline deposit over the wings?
Should be remove before attempting to take off.
Dangerous icing is frequently found in?
NS cloud.
It is safe to avoid a thunderstorm by flying under it?
False
The white crystalline deposit of ice that forms on all exterior surfaces of an aeroplane when water vapour turns directly into ice is called?
Hoar frost
The pressure gradient force acts?
At right angles to isobars, towards the low-pressure
The strength of the pressure gradient force depends most on?
The spacing of the isobars.
Coriolis force explains the tendency of wind to?
Turn left in the southern hemisphere.
Surface wind, when compared to the gradient wind flow, is found to be?
Veered to the right and slower
Compared to the gradient wind flow, the surface wind Overland will have?
Veered by 30° and slowed by 2/3
The term Geostrophic wind refers to the steady flow of wind?
Along straight isobars
Anticyclonic flow occurs?
About a high in the southern hemisphere.
Cyclonic flow occurs?
About a low in the southern hemisphere.
A katabatic wind will tend to reinforce?
A land breeze
The variations in wind and temperature in which normally occur with the passage of a cold front are?
The wind backs and temperature falls
A Fohn wind is likely to result in?
A lower humidity in the lee of the mountain at low level.
Best describes a squall line?
A low cloud moving rapidly in the warm air ahead of a cold front.
Which latitude would There be the greatest difference between the actual wind and gradient wind at 5000 feet AGL?
5° south
A statement which best describes a backing wind is?
It is changing direction anticlockwise.
For a katabatic wind to form, there must be?
A surface inversion .
Squall lines are most often associated with?
Thunderstorms.
Surface friction causes?
A decrease in Coriolis affect.
An aircraft heading directly from a high-pressure system to a low-pressure system will?
Drift towards the left.
Conditionally stable is said to exist when ?
Saturated air is unstable but dry air is stable.
Which conditions are most likely to produce radiation fog ?
No clouds 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 inside a thunderstorm?
Between 10,000 feet and 30,000 feet.
In which conditions are thunderstorms most likely?
Latitudinal heating of fast moving cold moist air stream
Which of the following cloud types is most likely to produce Virga ?
Thin altostratus.
Which is most likely to be encounted in Nimbostratus cloud?
Heavy continuous rain
The lifting of fog may be caused by?
An increase in wind strength.
The most common way for cumulus clouds to form is?
Rising air being cooled by expansion
Which phenomena in thunderstorm causes low level wind shear at some distance away from the cell.
Down draft
Where are tornadoes most likely to be encounted?
With widespread, severe thunderstorms
Latitudinal heating of cold air stream produces?
Instability, possibly thunderstorms.
Thunderstorm can occur well after a cold front has passed because?
The surface over which the cold air is passing is warmer than the cold air mass
Advection fog forms when?
Warm air passes over a cold surface
Thunderstorms are most likely to form when atmospheric conditions are?
Humid and unstable
A wind blowing up sloping terrain during the day could be?
Anabatic
The area in which a tropical cyclone is most likely to form is?
Over the Pacific ocean near 15° south
During the mature stage of a tropical cyclone the central surface pressure?
Remains constant.
The temperature at the base of a Strato cumulus cloud is -1°C. The cloud is 2500 feet thick, and the temperature at the Cloud tops is -5°C. Flight within the cloud is likely to encounter?
Rime ice
And which cloud type is clear ice most likely in flight above the freezing level?
Nimbostratus
