Question

What is the general direction of the Southwest Monsoon winds and where does it change?

Answer 1

Hint: Monsoon is the seasonal reversal in the wind system. The Trade winds move from the North-East to South-West direction which is reversed during monsoon.

Complete Answer: The term monsoon is derived from an Arabic word ‘Mausim’ which means season. Monsoon refers to the seasonal reversal in the wind system during a year.
During summer, the interior of Asia and India gets extremely hot. The air becomes hot and rises up creating a belt of low pressure. On the other hand, water in Indian ocean is comparatively cool creating a belt of high pressure. The pressure difference between Indian Ocean and North Central Indian Plains causes the air to flow from an area of high pressure to an area of low pressure i.e, from water to land.
This is the general movement of air in June from the Equatorial region of Indian ocean to the Indian Subcontinent in the South-West to North-East direction. This is exactly opposite to the direction of Trade Winds (North-East to South-West) that prevail during winter in India. This complete reversal of wind direction is known as Monsoon.
These winds on reaching the Southern tip of India divide into two branches: Arabian Sea branch and Bay of Bengal branch. The Arabian Sea branch moves towards Mumbai, Saurashtra-Kachchh and towards other parts of central and northern India. The Bay of Bengal Branch reaches Assam via southern states of India and then lofty himalayas deflects these winds towards northern plains where both the branches meet. These winds are moisture laden and cause rain throughout Indian subcontinent from June to september
During winter the pressure belts reverse and so is the direction. Therefore, the North-East trade winds prevail over India during winters i.e, they blow from land to sea causing a dry season. A part of the North-East winds blow over Bay of Bengal gathering moisture and causing rainfall in the Coromandel coast while the rest of the country is dry.
This implies that the Monsoon is the seasonal modification of the wind system during a year.

Note: Monsoon winds are irregular and can be affected by different atmospheric conditions. These winds are not equally distributed. Coastal areas like Kerala, West Bengal and Odisha receive heavy rainfall while interior regions receive less rainfall.