Which one of the following climatic regions of the world have a typical characteristic of seasonal reversal of wind ?
- (a)British type Climate
- (b)Mediterranean Climate
- (c)China type Climate
- (d)Monsoon Climate
Correct — D, Monsoon Climate. The word monsoon comes from an Arabic term for season, and a complete seasonal reversal of the prevailing wind is the one feature that defines the type. In summer the land heats faster than the ocean, a low-pressure area develops over the continental interior, and moisture-laden air blows from sea to land, bringing the rains. In winter the land cools faster, high pressure builds over the interior, and dry air blows from land to sea. The wind does not merely shift or strengthen; it turns round through roughly 180 degrees between the two halves of the year, and the whole rainfall regime turns with it. No other climatic type in this list is defined that way.
- (a)British type Climate — The cool temperate western margin type lies in the belt of the prevailing westerlies, which blow from the ocean in every month. That is why rain falls all year round there and why there is no dry season to reverse into.
- (b)Mediterranean Climate — The Mediterranean type does swing between a hot dry summer and a mild wet winter, and that is what makes it tempting. But the cause is the whole planetary wind belt sliding north and south with the sun, bringing westerlies in winter and subtropical high pressure in summer. The region moves between two wind systems; the wind itself does not reverse.
- (c)China type Climate — The warm temperate eastern margin type does carry a monsoonal tendency, and some textbooks even call it the temperate monsoon climate, so it is the sharpest of the three decoys. What separates it is that it has rain in every season and no dry half of the year, so the reversal is not the defining characteristic. The option that names the monsoon outright is the one the question wants.
World climates are usually taught by latitude and continental position, and each type carries one signature. The equatorial type has convectional rain all year. The Mediterranean type has a summer drought under subtropical high pressure. The British type has westerly rain in every month. The monsoon type is defined by a seasonal reversal of the prevailing winds, driven by the difference in how quickly land and sea heat and cool, and reinforced over South Asia by the seasonal migration of the intertropical convergence zone and by the barrier of the Himalaya.
The trap lies in confusing seasonality of rainfall with reversal of wind. Several types have wet and dry seasons; only one has winds that blow one way for half the year and the opposite way for the other half. Ask which climate would leave a sailing ship able to travel out in one season and home in another, and the answer picks itself — the Arabian Sea trade ran on exactly that rhythm for centuries. One incidental point about the printing is that the stem reads which one of the following climatic regions have, where the singular would call for has; the paper carries several such slips and the meaning is unaffected.
- A monsoon is a seasonal reversal of the prevailing wind, from sea to land in summer and land to sea in winter.
- The reversal is driven by the different heating and cooling rates of land and sea, which flip the pressure gradient between them.
- The south-west monsoon supplies the great bulk of India's annual rainfall, and its withdrawal brings the dry season.
- The Mediterranean type owes its wet winter to the seasonal migration of the westerly belt, not to any reversal of wind direction.
Several of these climates have a wet season and a dry season; only the monsoon type is defined by the wind itself turning round.
- Treating any climate with a wet and a dry season as a monsoon climate.
- Picking the Mediterranean type because its rainfall reverses between the seasons, when the wind belt is what moves.
- Forgetting that the China type is a humid subtropical climate with rain in all seasons.
Asked as a straight definition item — match one signature characteristic to the climatic type that owns it.
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
Answer(c) Monsoon climate
The same question in almost the same words, nine years earlier, with the Mediterranean type again offered as the decoy. Worth showing students side by side as proof of how directly UPSC-family papers repeat a settled definition.
The duration of monsoon in India extends for an average period of
- (a) 80 – 140 days
- (b) 100 – 120 days
- (c) 90 – 130 days
- (d) 100 – 140 days
Answer(b) 100 – 120 days
Moves from what the monsoon is to how long it lasts. The reversal defined here is what starts and ends that hundred-odd day season, so the two facts belong to one another.
- practice — not a real PYQ
The word 'monsoon' is derived from a term meaning
- (a)mountain
- (b)season
- (c)rainstorm
- (d)ocean current
Answer(b) season — the name captures the seasonal turning of the winds that defines the climate.
- practice — not a real PYQ
Hot dry summers and mild wet winters are the typical characteristic of which climatic type?
- (a)Equatorial climate
- (b)Mediterranean climate
- (c)Monsoon climate
- (d)Tundra climate
Answer(b) Mediterranean climate — the summer drought comes from subtropical high pressure, and the winter rain from the westerlies moving in.