UPSC Mains 2014 · GS I · Q19 · 10 marks · 150 words

Tropical cyclones are largely confined to South China Sea, Bay of Bengal and Gulf of Mexico. Why ?

हिन्दी में

उष्णकटिबंधीय चक्रवात अधिकांशतः दक्षिणी चीन सागर, बंगाल की खाड़ी और मैक्सिको की खाड़ी तक ही परिसीमित रहते हैं । ऐसा क्यों है ?

Cyclones

How a topper answered the closest question

Toppers wrote this one in a test series: “Discuss why the Bay of Bengal is more prone to cyclones than the Arabian Sea. Also, explain the reasons for the decrease in frequency of tropical cyclones during the Southwest monsoon season.”

Bhavika ChopraAIR 25 · CSE 2025 · 90 wordsTheir whole copy

Opening

The Bay of Bengal is warmer than the Arabian sea and hence more prone to cyclones that form near the Indian shoreline.

Body · points and prose

Diagram
[Map sketch of Indian subcontinent] Arabian sea (cooler) Bay of Bengal (warmer) (need 27°C SST for cyclones)

Timing of cyclones: Usually end of south-west monsoon, October, April in Bay of Bengal

Reasons for decrease in frequency in SW monsoon:

  1. Increase in vertical shear.
  2. Active movement of Bay of Bengal branch of monsoon.
Diagram
[Vertical cross-section of cyclone] EYE at center SEA SURFACE at 27°C Low Pressure area vertical shear high => cyclonic conditions are dissipated

FORMATION OF CYCLONE

However, the Arabian sea is now witnessing more cyclones due to:

  1. Warming due to climate change.

  2. Higher sea surface and ocean mean temperatures in Arabian sea.

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Source: UPSC, Civil Services (Main) Examination 2014, General Studies Paper I, Q19. The paper on upsc.gov.in. Themes and links to toppers’ answers are by UPSC Grade, not by UPSC.