Question

Give reasons for the following.

Monsoon winds retreat after September.

Answer 1

1. Apparent Southward Movement of the Sun: By September, the sun has moved southward toward the Equator and the Tropic of Capricorn. This causes a sharp fall in solar energy across the northern Indian landmass, cooling land.
2. Weakening of the Low-Pressure Trough: As northern India cools, the powerful low-pressure system above the Indo-Gangetic plains weakens. It can no longer attract or sustain the southwest monsoon winds, which are powerful and moisture-laden.
3. Development of High Pressure over Land: With the temperature dropping, a high-pressure system forms over the northern mainland. Air naturally goes from high to low pressure, altering wind direction.
4. Shift of the Monsoon Trough over the Ocean: The low-pressure center (Inter-Tropical Convergence Zone, or ITCZ) moves away from the Indian subcontinent and south across the warmer seas of the Bay of Bengal, pushing winds away from the land.