DGCA Meteorology: Mountain Waves Questions
44 exam-style Mountain Waves questions for the DGCA Meteorologypaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is
- Acirrus.
- Bcumulus mediocris
- Caltocumulus lenticularis.
Show answer
Correct answer: C. altocumulus lenticularis.
Standing waves set up downwind of mountains produce smooth, lens-shaped altocumulus lenticularis at the wave crests, the classic visual signature of mountain-wave activity.
- Q2
For mountain waves to form the wind speed for small mountains should be atleast
- A15 m/s
- B10 m/s
- C7 m/s
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Correct answer: C. 7 m/s
For mountain waves over small hills or ridges, the wind component across the ridge should be at least about 7 m/s (roughly 15 kt); larger mountain ranges require about 15 m/s.
- Q3
Rotor clouds are associated with:
- ATurbulence above the cloud
- BTurbulence below the cloud
- CNo turbulence
Show answer
Correct answer: B. Turbulence below the cloud
Rotor clouds form under mountain waves, with choppy air below from swirling winds.
- Q4
For mountain waves to form the wind speed for large mountains should be atleast
- A7 m/s
- B15 m/s
- C10 m/s
Show answer
Correct answer: B. 15 m/s
For mountain waves to form over large mountain ranges, the wind component across the ridge should be at least about 15 m/s (roughly 30 kt), roughly double the requirement for small hills.
- Q5
At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is
- Aaltocumulus lenticularis.
- Bcirrostratus.
- Ccumulus mediocris.
Show answer
Correct answer: A. altocumulus lenticularis.
The crests of orographic (lee) waves are marked by altocumulus lenticularis, smooth lens-shaped clouds that remain quasi-stationary as air condenses on the rising side of the wave and evaporates on the descending side.
- Q6
For mountain waves to form the wind speed for large mountains should be atleast
- A10 m/s
- B7 m/s
- C15 m/s
Show answer
Correct answer: C. 15 m/s
Over large mountain ranges a cross-ridge wind of at least about 15 m/s (around 30 kt) is required for mountain-wave formation, compared with about 7 m/s for small hills.
- Q7
The vertical extent of the friction layer depends primarily on
- Aroughness of surface, temperature, local time
- Btemperature, local time, environmental lapse rate
- Cstability, wind speed, roughness of surface
- Dwind speed, roughness of surface, temperature
Show answer
Correct answer: C. stability, wind speed, roughness of surface
This Explanation is Coming Soon
- Q8
Low level wind shear is likely to be greatest
- Aat the top of a marked surface-based inversion
- Bat the condensation level when there is no night radiation.
- Cat the condensation level when there is strong surface friction
- Dat the top of the friction layer
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Correct answer: A. at the top of a marked surface-based inversion
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- Q9
Which cloud type may indicate the presence of severe turbulence?
- ACirrocumulus
- BNimbostratus
- CAltocumulus lenticularis
- DStratocumulus
Show answer
Correct answer: C. Altocumulus lenticularis
This Explanation is Coming Soon
- Q10
Low level vertical wind shear can be expected during the night
- Ain association with radiation inversions
- Bin unstable atmospheres
- Cand early morning only in winter
- Dand early morning only in summer
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Correct answer: A. in association with radiation inversions
This Explanation is Coming Soon
- Q11
What is the effect of a strong low level inversion?
- AIt results in good visual conditions
- BIt promotes vertical windshear.
- CIt promotes extensive vertical movement of air.
- DIt prevents vertical windshear
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Correct answer: B. It promotes vertical windshear.
This Explanation is Coming Soon
- Q12
A wide body aircraft takes off on a clear night in Dhahran, Saudi Arabia. Shortly after take off the aircraft’s rate of climb drops to zero. This can be due to
- Avery pronounced downdrafts
- Blow relative humidity
- Ca very strong temperature inversion
- Dsand/dust in the engines
Show answer
Correct answer: C. a very strong temperature inversion
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