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UPSC Prelims 2014 · Environment · Nature’s Machinery
The seasonal reversal of winds is the typical characteristic of
- (a) Equatorial climate
- (b) Mediterranean climate
- (c) Monsoon climate
- (d) All of the above climates
Show the answer and explanation
Answer: (c) Monsoon climate
Land–sea heating differences and the shift of the ITCZ reverse the winds between summer and winter.
The idea
Land heats and cools faster than the sea. In summer the land is hotter, air rises over it, and moist wind blows in from the sea. In winter the land is colder, air sinks over it, and dry wind blows out to sea. The wind changes direction with the season: that is a monsoon.
Summer: hot land → low pressure → south-west wind from the sea → rain → Winter: cold land → high pressure → north-east wind from the land → dry
Why the others are wrong
(a) Equatorial winds converge all year; they don’t reverse.
(b) The Mediterranean has winter rain from westerlies, not a wind reversal.
Also know
The winter wind picks up moisture over the Bay of Bengal and gives rain to the Tamil Nadu coast. Monsoon climates are also found in South-East Asia, northern Australia and West Africa. India’s monsoon is affected by the Tibetan plateau, the jet streams and El Niño.
🔒 Monsoon (Arabic mausim = season) = seasonal reversal of winds.