Consider the following conditions favourable for the formation and intensification of Tropical Storms : 1. Presence of the Coriolis force 2. Upper divergence above the sea level system 3. High variations in the vertical wind speed Which of the conditions given above is/are correct ?
- A.1 only
- B.2 only
- C.1 and 2
- D.2 and 3
Correct answer
Explanation
The correct answer is C, 1 and 2. Tropical storms need the Coriolis force and upper-level divergence, but they need small, not high, variations in vertical wind speed.
The standard conditions for a tropical cyclone are a large sea surface with temperature above 27°C, enough Coriolis force to set the air spinning, small changes in wind speed with height, a pre-existing weak low-pressure area, and divergence of air above the sea-level system. Upper divergence removes the rising air and keeps surface pressure falling, so the storm deepens. The Coriolis force is zero at the equator, which is why cyclones rarely form within about 5° of it.
A is wrong because upper divergence is also a necessary condition. B is wrong because without the Coriolis force the winds cannot form a rotating vortex. D is wrong because strong vertical wind shear tears the storm's structure apart and stops it from growing.
Exam tip: warm sea above 27°C, Coriolis force, low wind shear, a prior low and upper divergence: the five needs of a tropical cyclone.
Practice Questions
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- A.India
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- C.Canada
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- A.Malabar Coast
- B.Garo Hills
- C.Sunderban Delta
- D.Desert Region
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1. Gauge conversion
2. Track electrification
3. Automatic signals
Select the correct answer using the codes given below :
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- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
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- A.Cumulus cloud
- B.Stratus cloud
- C.Nimbus cloud
- D.Cirrus cloud
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- A.Northern mountains
- B.Peninsular plateau
- C.Northern plains
- D.Coastal plains
Show answer
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