Meteorology Flashcards
The out-flowing in a mature thunderstorm
Usually is greater in the direction of the thunderstorm
Why is the temperature colder in polar region
The solar radiation is lesser per unit area as compared to the tropics
What is a visual sign of a mature thunderstorm
Cumulus growing over layered clouds like stratocumulus or altocumulus
There is a sea Breeze in the late morning of a summer. Which of these will explain what happens to the surface conditions above the land when the wind moves across?
Temperature will drop, dew point will increase
How is an airmass created?
When air remains stagnant over land or sea and develops similar properties
Which is true of polar front jet streams
They are located in the warm sector and are ahead of the frontal area at latitudes of 40-50deg
Questions asks about how is hail generated
Option chosen was the one that says strong updraughts in CB, with most of the cloud above freezing level and with supercooled water droplets.
How is SWD formed
… due to lack of freezing nuclei, the water remains in unstable state below 0degC as SWD
Image shown of flight from HK to SG. They ask what is the average wind speed at 5N
070/40, -53degC
Which of the following will most likely lead to the formation of Low level stratus clouds
Moist air moving over a relatively cooler sea, with wind speeds in excess of 15kts
How do you distinguish cumulus clouds
Segregated segment of clouds….
Rime ice
Instantaneous icing with small SWD
Which of this is the correct code used in METAR?
GR: Hail or big snow, precipitate with diameter more than 5mm
Wind shear at a friction layer is most pronounced when
Density of friction layer is maximum just before dawn
What is conduction
“… in direct contact with each other and at different temperatures so there is some heat transfer…”
After passage of warm front, 1 hour later you are in the warm sector. What would you expect to see in the warm sector?
More or less constant QNH, light and intermittent rain, Low and extensive clouds, Low vis
In the SH, where do trade winds originate from
From sub tropical high belt, and move from SE
What’s the expected weather like in South Asia under the SW monsoon?
Option with most severe conditions.
Heavy turbulence, thunderstorms, etc
What’s the length of jet stream
2000nm
Definition of subsidence inversion
When air sinks, it heats up adiabatically…
Anti-cyclonic at the surface, cold surface, how to pressure levels appear
Bulges down, and decrease in strength as altitude increases
Bergeron theory of rain formation
Some supercooled water droplets will turn to ice and grow by sublimation and fall as snow or rain, depending on temperature
Weather conditions for blocking high systems
Good weather for Long time
What type of wind shear may be reported in a METAR
All reported wind shear
What is a mistral
A valley wind
RVR measured in
Metres
Tornadoes are formed by
Strong up currents within CB
Which of the following best describes the formation of tornadoes
Strong updraft within CB
There is Low pressure near the surface and there is some pressure aloft. Does it bulge up or down
Bulge down rises and reduces in size
When is diurnal variation the greatest?
Mid-afternoon
Diurnal variation of relative humidity
RH decreases by day, increases by night
FL180 which charts do you use
500hPa
What is true altitude?
Actual altitude above AMSL
Given FL330, calculate true altitude if ISA deviation is +7degC
33924ft (closest is 34000ft)
Which is the severe most quadrant for the Cyclones in the SH?
Left front quadrant
Pressure gradients are measured for practicality purposes
From high to Low pressure
Pressure gradient is measured
Perpendicular to isobars
What is the weather at a Col
Not much weather
What is the weather around a Col in winter
Low vis and fog
What weather can you expect in Col winter
Light winds, fog…
What is set on AC altimeter if it shows 0ft on the ground
QFE
What affects the type of icing
Type of droplets, water vapour content and air temperature
What are the conditions to clear ice formation
When droplets are large
When an air mass goes to a warmer area what happens
Becomes unstable, convection occurs, Cu Cb form in day with good vis
Why is SALR lower than DALR
Due to heating caused by condensation and release of latent heat
Why are poles colder than equator
Due to sun more directly overhead equator than poles
Solar radiation is reflected back to space due to
Clouds
What are the weather phenomena indicating an area of jetstreams
Cirrus streaks, change in wind speeds and CAT
What are the met signs that you are approaching a jet stream while flying
Change in temperature, winds and drifts, CAT
Which area of jet stream would you experience the worst CAT
Core to the Low pressure side
Severe turbulence is
Large and abrupt movement of AC in the 3 axes, pilot losing control of AC definitely, but briefly, and loose articles gets tossed
What is an AIRMET
MET info along air route
Info for met conditions
Geostrophic wind is the balance of what
Coriolis and pressure gradient force
What is an orographic depression
Flow of air meets mountain range at large angle , causing air to flow around, instead of over the TOP
During months of June to September, where is the wind coming from Singapore
S and SW monsoon
What are tradewinds characteristics
Steady, 10kts
An air mass at its origin is
Stable
What happens to the winds and pressure when a warm front passes you
It veers
Size of drizzle
0.2mm to 0.5mm
In what units is wind reported in TAF and METAR
True/kts
What is the weather in a quasi-stationary front
Little/no weather
Where will the TU be at 100Z
- 440 to 118.00
224. 40 to 11.800
During the summer of SH where do you expect the ITCZ to be in the South Pacific
Mainly below equator but slightly above in central South Pacific
Why is the main cause for general circulation
Transfer of heat from equator to polar region
What is the average altitude and temp of tropopause for tropical regions
55000’ to 60000’ , -70degC
The tropopause over the equator is at FL_____, while it is at FL_____at the poles. Compared to the poles, the tropopause at the equator is
520, 280, colder
The tropopause height is higher
Over the equator and the temperature is colder
260/55 250/75 Variation 9degE TAS 457kts Find the true heading
220deg / 410kt
Where does the Harmattan blow to
Hot, dusty winds blowing across Sahara desert
Where does the cirrus cloud form at a jet stream
Below towards warm side
What weather is expected when tropical maritime air blow towards U.K. or Europe during winter
Fog/Stratiform
What weather can you expect when passing through a cold front in NH
Steady or slight veer to NW, Cu Cb
You left your aircraft for 3 hours coming back after to find your altimeter reading has increased. What is the likely reason?
QNH decreased
Where is a RVR reading taken from
Specific location and down one direction
The met measurement of RVR is described as
Distance measured by an electronic device where intensity of light a known distance away is measured by a photoelectric cell
Which would be a correct instrumented RVR reading
R20R/300U
RVR 400 450 500. Where are they measured?
Touchdown, midpoint, end-point
Cyclone formation in the South Pacific between the meridian
140E 160W
Tropical cyclones in the SW Pacific usually occurs
Between 5degS and 20degS
Where are the tropical storms found in the Pacific in the Southern Hemisphere
5-25 degrees South, 140W to 160E
A thermal wind is
Affected by Buys Ballot Law and blows to the right when moving from an area of Low pressure to High pressure in the SH
The ozone layer
Absorbs UV radiation and warms the atmosphere
Which of the following corresponds to Koppen’s climate classification
A: Tropical B: Arid/Dry C: Temperature (warm) D: Continental (snow) E: Polar
Where will wake turbulence be encountered
Below and just behind the flight path of a clean, heavy aircraft flying at Low speed
What is the ISA condition at sea level
15degC, 1013hPa
A high level chart with height specific isobaric levels is known as
A constant pressure chart
What is the rate of accretion of icing over mountains like?
Heavy because atmosphere is disturbed due orohraphic effect
Why icing risk is higher in orographic lifting
Air being forced up contains more supercooled water droplets
When will you expect a wet monsoon to occur over Singapore?
Oct - Mar (or Jan-Mar)
What happens when a given parcel of air is cooled?
Relative humidity increases, dew point & absolute humidity remains the same
What are the required conditions for the formation of TRS
Water 27degC, <1000hPa, convection
Surface chart with a high to the left of Ireland and Low over north west France. Determine direction of surface wind
030T
In summer over British isles, what sort of weather will you expect with a tropical continental air mass
Warm or very warm weather with dusty conditions
A jet stream is formed from a
Horizontal temperature difference
What causes nocturnal thunderstorms in the tropics
The sea is being warmed and air cooling at night
What triggers precipitation in the air masses
Orographic lifting and convective currents
With respect to jetstreams, what are the relative height of a tropopause
The tropopause is higher on the tropical side than the polar side
For which altitude would you use a 500hPa chart
FL180
Refer to figure above, what is the flight level you can expect CAT along the flight path from Sydney, in red?
FL250 - 530
Refer to figure above, what is the approx speed of the jet stream you can expect when flying at FL390 along the flight path from Sydney, in red?
160kts
Refer to figure above, what is the tropopause height along the flight path from Sydney, in red, towards Hong Kong?
FL420 - 500
With high level of divergence, air at the surface would,
Converge and ascend
With high level divergence, air at the surface would
Diverge and descend
Refer to the figure above, what is shown
A curve with semi circles on TOP
Warm front
Which of the following represents a squall line
—— .. ——- .. ——-
In a blocking high in the South Pacific, the vertical profile would be
Weak divergence at lower levels and strong convergence at high levels
What happens in a blocking anticyclone
Subsidence, intense in upper troposphere, weak in lower troposphere
Where can info about volcanic ashes in the atmosphere be found
In SIGMET and in ACCA notices
Volcanic ash advisory is reported to who / goes to who
Pilots
What does the above symbol represents on a weather chart
Looks like a bell, with 3converging sticks on TOP
Volcanic eruption
Which conditions best promotes the development of radiation fog
Night time or dawn with clear skies, light wind and high relative humidity
What does advection fog form
Over cold land or sea with warm moist air
When temp is said tone ISA +2degC, it means
At the pressure altitude, temp is 2degC warmer than ISA temp typical of the altitude
Diff between FL and altitude
FL is constant pressure level and altitude is constant distance from MSL
On which surface will ice accretion occur first
Leading edge of tailplanes and aerials
First aircraft icing most likely to be
On wings upper and lower surface
How does surface and speed affect the rate of ice accretion
Sharp surfaces at high speed increase accretion rate
Which of the following is correct
About two letter code
GR: Hail, iceballs of diameter greater than 5mm
Which of the following does not favour the formation of standing mountain Lee waves
Winds varying direction as altitude changes
What factors are required for standing waves
Low level 15kts and increasing with altitude and a stable layer above the ridge blowing nearly or perpendicular to the ridge
The following is a forecast at an aerodrome
Tons of numberssss
Local magnetic variation is 20degW. If you are flying inbound on a holding pattern at 5000’ at 100degM, what will be the headwind component
-10
Geostrophic wind is caused by
PGE, coriolis force
Coalescence theory is
Assumption presence of the range of droplets sizes larger falling faster to meet smaller droplets and fall as rain
Bergeron theory is unable to explain the formation of precipitation uncertain cases because
Not all water droplets are supercooled
In an occluded front
Cold air behind the cold front undercuts the warm air and cold air ahead of the warm front , and it is called a cold occlusion
What is the weather at a cold occlusion
Embedded Cb. Most of the precipitation is behind the surface position of the occlusion
Low level wind shear associated with the Top of the friction layer will be at its
Maximum when layer density is greater before dawn
Main diff between microburst and downburst, is that microburst
Can only occur singly
Virga is
Rain that sublimates before reaching ground, absorbing latent heat and cooling surrounding air
In convective clouds
Saturated air is cooled, water vapour condenses, releasing latent heat, heating the cloud relative to surrounding air and intensifying the convective effect
Water vapour in air
Cannot be seen as it is a gas
At 40degN latitude, the prevailing wind is
Westerly
At 3000ft just above a Low level inversion, what kind of cloud do you expect
CB
Flying at 3000ft in cloud, you experience light turbulence and light icing, from which cloud is this the most common
SC
How is radiation fog lifted
Insolation
What are the conditions that favours radiation fog to dissipate
Insolation and strong wind blowing the surface
What causes year round thunderstorms in the tropics
ITCZ
The tropopause can be defined as
Where the decrease in temp with altitude ceases
When a particle is struck and part of the solar radiation is reflected back to space and part of it warms the atmosphere, this is known as
Reflection
How does the wind direction and strength change from surface to upper levels in the Southern Hemisphere
It is constant in the friction layer but suddenly increases speed and backs above the friction layer
At 18Z, where is TS PACHU expected to be at?
22.32N 116.00E