Vayudoot Aviation

1. Isolated thunderstorms of a local nature are generally caused by

frontal lifting (warm front).

frontal occlusion.

thermal triggering.

frontal lifting (cold front).

2. Which of the statements is true concerning squall lines?

Severe squall lines always move from northwest to southeast

Severe squall lines only occur in the tropics

For severe squall lines a TAF is issued

For severe squall lines a SIGMET is issued

3. In Central Europe when is the greatest likelihood for thunderstorms due to warm updrafts?

Early morning.

Mid - afternoon

Late morning.

Around midnight

4. What are the requirements for the formation of a thunderstorm?

A cumulus cloud with sufficient moisture associated with an inversion

An adequate supply of moisture, conditional instability and a lifting action

A stratocumulus cloud with sufficient moisture

Water vapour and high pressure

5. In addition to a lifting action, what are two other conditions necessary for thunderstorm formation?

Unstable conditions and low atmospheric pressure

Stable conditions and high moisture content

Unstable conditions and high moisture content

Stable conditions and low atmospheric pressure

6. What is a microburst?

A concentrated downdraft with high speeds and a higher temperature than the surrounding air.

An extremely strong wind gust in a tropical revolving storm.

A small low pressure system where the wind circulates with very high speeds.

A concentrated downdraft with high speeds and a lower temperature than the surrounding air.

7. Which thunderstorms generally develop in the afternoon in summer over land in moderate latitudes?

Cold mass thunderstorms

Warm front thunderstorms

Occlusion thunderstorms

Airmass thunderstorms

8. Which of the following statements describes a microburst ?

A high speed downburst of air with a generally lower temperature than its surroundings

A small low pressure system where the wind circulates at high speed

An extremely strong wind gust associated with a tropical revolving storm

A high speed downdraft of air with a higher temperature than its surroundings

9. What weather condition would you expect at a squall line?

Strong steady rain

Fog

Strong whirlwinds reaching up to higher levels

Thunderstorms

10. The initial phase of a thunderstorm is characterized by

frequent lightning

rain starting at surface

continuous up draughts

continuous downdraughts

11. Where is a squall line to be expected?

In front of an active cold front.

Behind a cold front.

At the surface position of a warm front.

In front of a cold front occlusion at higher levels.

12. Which of the following causes echoes on meteorological radar screens?

Water vapour

Fog

Hail

Any cloud

13. A microburst

has a diameter up to 4 km

occurs only in tropical areas

has a life time of more than 30 minutes

is always associated with thunderstorms

14. A gust front is

another name for a cold front

normally encountered directly below a thunderstorm

formed by the cold air outflow from a thunderstorm

characterized by heavy lightning

15. An airborne weather radar installation makes it possible to detect the location of

stratocumulus and its vertical development

cumulonimbus, but provided that cloud of this type is accompanied by falls of hail

all clouds

zones of precipitation, particularly liquid-state precipitation, and also their intensity

16. What is the approximate maximum diameter of a microburst?

50 km

4 km

400 m

20 km

17. During which stage of thunderstorm development are rotor winds characterized by roll clouds most likely to occur?

Cumulus stage and mature stage.

Cumulus stage.

Dissipating stage.

Mature stage.

18. What are the meteorological prerequisites, at low level, for thunderstorms formed by lifting processes, over land?

Subsidence, inversion.

High air pressure (> 1013 hPa), high temperatures.

Low temperatures, low humidity.

High temperatures, high humidity

19. Aircraft struck by lightning may sometimes get considerable damage and at least temporarily the manoeuvring of the aircraft will be made more difficult. Which one of the following statements is correct?

An aircraft made by metal has a certain capacity to attract a lightning, but the lightning will follow the surface and therefore no damage will be caused.

Aircraft made by composite material can’t conduct a lightning and will therefore very seldom be struck

Aircraft made by composite material may get severe damage, the crew may be blinded and temporarily lose the hearing

An aircraft has in the atmosphere the same qualities as a “Faradays cage”, which means that struck of lightning seldom occurs. But if it happens, the result will be an occasional engine failure. The crew may get a shock.

20. How long does a typical microburst last?

About 30 minutes.

1 to 2 hours.

1 to 5 minutes.

Less than 1 minute.

21. Continuous up draughts occur in a thunderstorm during the

cumulus stage.

dissipating stage

mature stage.

period in which precipitation is falling.

22. Large hail stones

are typically associated with severe thunderstorms

are entirely composed of clear ice

only occur in thunderstorms of mid-latitudes

only occur in frontal thunderstorms

23. Thunderstorms reach their greatest intensity during the

dissipating stage.

cumulus stage.

period in which precipitation is not falling.

mature stage.

24. In which of the following areas is the highest frequency of thunderstorms encountered?

Temperate

Tropical

Subtropical

Polar

25. The diameter and the life time of a typical microburst are in the order of

4 km and 30-40 minutes

4 km and 1-5 minutes

12 km and 5-10 minutes

8 km and 5-15 minutes

26. In which stage of the life cycle of a single thunderstorm cell occur both up- and downdrafts simultaneously?

In all stages

Mature stage

Dissipating stage

Cumulus stage

27. A microburst phenomenon can arise in the

downdraught of a cumulonimbus at the mature stage.

up draught of a cumulonimbus at the mature stage.

downdraught of a cumulonimbus at the formation stage.

up draught of a cumulonimbus at the growth stage.

28. Which thunderstorms move forward the fastest?

Thermal thunderstorms.

Frontal thunderstorms.

Thunderstorms formed by lifting processes.

Orographic thunderstorms.

29. What feature is normally associated with the cumulus stage of a thunderstorm?

Rain or hail at the surface

Frequent lightning

Roll cloud

Continuous updraft

30. During the life cycle of a thunderstorm, which stage is characterized predominantly by downdrafts?

Mature stage

Anvil stage

Cumulus stage

Dissipating stage

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