Met General 200 Questions Flashcards
That part of the Earths atmosphère where most of the clouds and précipitation are Found is?
Troposphère
Statement with respect to the tropopause
- Lower over the pôles
- Higher over the equator
- Température at the tropopause is colder over the equator
The Height of the tropopause higner over ?
The equator: density of the air in this région is less and therefore Higher.
The Height of the tropopause Will tend to be Higher in?
-In warmer air mass
-When MSL pressure is high
Région of the atmosphère between stratopause and mesopause is?
Mesosphere
The Sun emits large amounts of ultraviolet radiation and is largely absorbed by a colorless gas that is found at varying amounts throughout the atmosphere. This gas is known as ?
Ozone
The earth’s surface is heated by?
Short wave solar (ultraviolet) radiation
What is the intertropicale convergence zone (ITCZ)
Is the area on the earth where solar radiation is at its strongest
Why does the ITCZ move south during winter months?
The northern hemisphere becomes titled away from the sun during winter meaning the point of maximum solar radiation striking the earth moves southward
The lower atmosphere is heated by?
-Conduction
-long wave solar (infrared) radiation
Temperature in the lower stratosphere approximate those?
Of the tropopause
In the international atmosphere (ISA) The temperature at sea level is 15°C and the pressure is 1013.2 hPa. What would be the ISA temperature for FL300
-45°
The actual temperature at FL280 IS -48°C. How would this temperature be expressed in terms of an ISA deviation?
ISA -7°C
If you are flying at 34 000’ with a SAT of -50°C and the tropopause was actually at 30 000’ where SAT was -51°C, what is the deviation from ISA?
You are flying at 38 000’ with a SAT of -50°C and the tropopause was actually at 44 000’ where SAT was -65°C, what is the deviation of ISA?
As air move horizontally over the earth in the N. Hemisphere, the air is deflected to the right. This is known as the Coriolis and it caused by the ?
Rotation of the earth
Where Coriolis is stronger?
Coriolis is stronger nearer to the poles
Vertical air currents are often created within the atmosphere by varying means. A process that will lead to rising air is known as ?
Convection
Where would experience the LEAST diurnal range in temperature?
Temperate zone oceans
True statement about warming
Convection is more likely to occur over water-free surfaces
The lifting process responsible for the choppy type of turbulence often encountered during flight within the lower 3000’of the troposphere is?
Mechanical turbulence
Lifting agent?
-Convection
-Mechanical turbulence
-Convergence
Meteorologists use the term convergence to detect air that is?
Flowing along the earth’s surface from areas of higher pressure into and converging at an area of lower pressure
Which processes can result in expansional cooling, subsequent condensation and formation of cloud?
Overrunning
Define overrunning?
It refers to how fast warm air rises vertically as it flows up along the frontal surface over the retreating cold air.
The clouds and precipitation often associated with a cyclone are due to?
Surface convergence and ascending air
What would be used to describe the process whereby a rising, expanding parcel of air does not undergo any heat transfer in or out the parcel as it ascends?
Adiabatic
Subsiding air, even if it is initially saturated, will?
Warm at the dry adiabatic lapse rate
With respect to air that is descending rapidly down the lee slopes of a mountain range?
This air will warm at the dry adiabatic lapse rate almost immediately after the start of its descent
When air side normally the relative humidity will?
The relative humidity decrease
When air ascends, its ability to contain moisture?
Decrease
During the condensation process?
Latent heat is released to the surrounding air
When condensation occurs in an unstable air mass, the stability of the air tends to become ?
More unstable as heat is released to the surrounding air
With a surface temperature of 28°C and a dewpoint temperature of 16°C reported at your airport, you would predict the base of any convective cloud that might form to be approximately:
4900’ AGL
With respect to a rising parcel of air which commences to ascend from a sea level airport where the temperature is 30°C, what would be its temperature at 14 000’ above sea level of its became saturated at 6000’ ASL.
+0°C
When discussing the stability/instability of the atmosphere, we are referring to:
A property of the atmosphere that suppresses or promote vertical motion
The stability of warm, dry air depends on the relationship between the?
Dry adiabatic lapse rate and the environmental lapse rate
Stable air is most likely to be associated with?
Sustained low visibility
Haze layers, drizzle and fog ares features of?
Stable air
One weather condition that may affect visibility in unstable air is?
Snow showers
Stable air becomes unstable as a result of?
Subsidence
A good signpost of mid-level instability would be the pressure of?
Altocumulus castellanus
What effectively inhibits or blocks rising air?
An inversion
The pilot of an aircraft would expect the smoothest low level flight during a hot summer afternoon when passing over what surface features?
A lake
A pressure of 200 hPa is closest to what levels in the ICAO standard atmosphere?
FL390
FL450 is associated with which pressure level in the ICAO standard atmosphere?
150 hPa
The vertical distance between any two specific pressure level is?
Less in cold air than in warm air
The height of a pressure level (ex: 500mb) will be tend to be found at?
A lower level in a colder air mass
The height of a pressure level will?
Become lower when a low is deepening
Flying in the lower levels towards the center of an anticyclone which has a strong pressure gradient, a pilot would expect?
High winds
Increasing barometric pressure
When flying towards a ridge of high pressure at FL200, what happens to the height of the pressure level and your true altitude?
Pressure level goes up and your true altitude goes up
When flying at FL200 towards an area of colder air on the surface of the earth, what happens to the height of the pressure level and your true altitude?
Pressure level goes down and your true altitude goes down
When flying at FL370 towards a ridge of high pressure and an area of warmer air on the surface of the earth, what happens to your indicated altitude (shown on your altimeter) and your true altitude?
Indicated altitude stays the same, but your true altitude goes up
An aircraft is parked on the apron. You go home for the night. During the evening, cold air moves into the vicinity of the airport. When you return to your aircraft in the morning, what does the altimeter show?
There will be no change in the altimeter’s reading
What statement relating to an anticyclone is true ?
-Fair weather and clear skies normally prevail within the region of an anticyclone
-an anticyclone is generally characterized by a downward vertical movement
-anticyclones can be described as strong or weak and strengthening or weakening
Surface highs and lows develop as a result of ?
Upper level convergence and divergence forcing air to sink or rise respectively
A trough is?
An elongated area of relatively low atmospheric pressure
A neutral area, not bounded by any one isobar, within which light winds are blowing and the weather is changing very slowly, exists between two high and two low pressure systems. The name given to this indefinite pressure area is?
A col
During descent from 3000’ AGL to the surface, you would expect the wind to?
Back and decrease
The wind at 3000’ over the land is parallel to the isobar at 30kt. What would be the most probable angle to the isobar and speed of the surface wind assuming it is not affected by local topography?
30° / 20kt
Given the same pressure gradient over the land and over the adjacent water, what is the most probable wind angle to the isobars and wind speed over the water if the surface wind over the land is blowing across the isobars at an angle of 30° and at a speed of 30kt?
20° / 40kt
A flight from Vancouver to Montreal at a constant pressure level experiences winds that gradually veer from the southwest to the northwest. The aircraft’s actual height above mean sea level will have: (hint: port drift -A/C true altitude is increasing; starboard drift A/C true altitude is decreasing)
Increased for a time and then decreased steadily thereafter
If the temperatures to the southwest today are warmer than those to the Northwest, the winds aloft would be blowing from the: (recall buys-ballots law - with your back to the wind, your left hand will point to the area of the lower pressure; for upper level winds, your left hand will point to area of lower temperatures…)
Southwest
What relate to density altitude?
-The density altitude is that altitude in the standard atmosphere which corresponds to a given density value.
-An increase in density altitude corresponds to a decrease in density.
-The density altitude for a given aerodrome is changing continually in response to changes in pressure and temperature.
An aerodrome’s density altitude is calculated with a flight computer using the?
The aerodrome’s pressure altitude matched with the aerodrome’s outside air temperature correct in terms of ASL
An aircraft’s true altitude would be greater than its indicated altitude in conditions of ?
Warm air and high pressure
What statements is true with respect to the term MSL pressure?
Is is station pressure reduced to MSL using the average surface temperature for the last 12h.
Altimeter setting is?
Station level pressure reduced to MSL assuming ISA conditions
It is essential that a pilot flying in the standard pressure region closely monitor terrain clearance, when:
Pressure and temperature are low
An aircraft descends from FL380 for an approach to the Kelowna airport. During the descent, the pilot forgets to reset the altimeter subscale. If the published decision height (DH) is 2060’ ASL, what would be the actual height of the aircraft on reaching the indicated DH?
METAR CYLW 281700Z 18010KT 5SN-SHRA OVC015 10/06 A2962 RMK SF8 SLP150
1760’ ASL
Compare two aircraft on approach - the 1st aircraft is flying the approach in standard atmospheric conditions; the 2nd aircraft in colder than standard conditions. Both aircraft arrive over the final approach point/fix at the altitude that is shown on the approach plate (to temps correction) what is the second aircraft’s altimeter reading in relation to the first, and what is the results?
The second aircraft’s altimeter will be over-reading, and therefore the aircraft will be lower than the published altitude.
Aircraft in colder than standard conditions. On an RNAV/RNP approach. What will happen to the slope of the approach flown by the aircraft?
The aircraft will fly a shallower approach path and touchdown with zero temperature error on the altimeter.
The relationship between the amount of water vapor actually present in the air and the maximum possible amount of water vapor that could be held by the air at that temperature and pressure (without condensation occuring) is expressed by what?
Relative humidity
The height of a cloud base is most dependent upon the ?
Moisture content of the air
Clouds and precipitation are common in areas?
Of ascending air
What type of cloud frequently forms as a result of evaporation from rain rather than from expansional cooling?
Stratus cloud
If the air mass is moist and stable with mechanical turbulence present in the lower levels, what type of clouds can you expect to be present?
Stratus et stratocumulus cloud
Rain droplets or snowflakes that fall from cumuliform cloud and evaporate or sublimate before reaching the ground is called?
Virga
Flying through or underneath virga usually results in?
Chopping flying conditions due the cooling effect as water droplets evaporate back into a gaseous state causing the more dense air to sink rapidly creating a form of wind shear
Drizzle forms through the ?
Condensation and coalescence processes occuring in Stratus cloud
Snow falling from a layer of stratocumulus cloud would indicate that
The liquid water content in the cloud is decreasing?
An airport weather observer reports snow grains; this type of precipitation would imply:
The freezing drizzle is present aloft
A large area of land or ocean of relatively uniform characteristics and above which an air mass can form, is known as a ?
Source region
A true statement with respect to air masses would be?
Air masses are classified according to their moisture content