The most specific place of origin of Western Disturbances active in…
2023
The most specific place of origin of Western Disturbances active in North-Western India during the winter season is
Answer: C. Mediterranean coastal area of Western Asia — Concept: A western disturbance is an extratropical (mid-latitude) cyclone. Unlike a tropical cyclone it is not driven by a warm ocean surface; it develops…
- A.
Asia Minor
- B.
Western Asia
- C.
Mediterranean coastal area of Western Asia
- D.
More than one of the above
- E.
None of the above
Attempted by 12 students.
Show answer & explanation
Correct answer: C
Concept: A western disturbance is an extratropical (mid-latitude) cyclone. Unlike a tropical cyclone it is not driven by a warm ocean surface; it develops through baroclinic instability — the sharp horizontal temperature contrast carried across the mid-latitude westerly flow — and is then steered from west to east by the subtropical westerly jet stream. Its place of origin is therefore the region in which the system first appears as a distinct low within that westerly flow, before it begins its eastward journey.
Application: For the winter systems that reach north-western India, that region is the Mediterranean — the eastern Mediterranean Sea together with the Western-Asian coastal belt fringing it, whose warm sea surface also loads the system with the moisture it later releases. The onward track is:
A low first appears over the eastern Mediterranean and its Western-Asian coastal belt, where the westerly flow is strongly baroclinic and the warm sea surface supplies abundant moisture.
The subtropical westerly jet stream, which in winter shifts south to lie over the Himalayan foreland, picks the system up and steers it eastward.
The system crosses Iraq, Iran, Afghanistan and Pakistan, gathering some extra moisture on the way from the Persian Gulf, the Red Sea and the Arabian Sea.
It arrives over Jammu & Kashmir, Himachal Pradesh, Punjab, Haryana, Delhi, Rajasthan and western Uttar Pradesh, giving the winter rain locally called mahawat — vital for the standing rabi wheat crop — along with snowfall in the western Himalaya.
Cross-check — how the three named places compare:
Place named | How it relates to the place of origin |
|---|---|
Mediterranean coastal area of Western Asia | The continent’s eastern-Mediterranean seaboard, running along southern Anatolia and the Levant. Standard sources — NCERT and the India Meteorological Department — locate the formation of these lows in this Mediterranean sector, and the official BPSC key marks this option correct. |
Asia Minor | The Anatolian peninsula. Its southern shore is part of the Mediterranean seaboard, but the peninsula as a whole is chiefly the landmass the tracks cross; sources name the Mediterranean sector, not interior Anatolia, as the source region. |
Western Asia | The entire continental sub-region — Anatolia, the Levant, the Arabian Peninsula, the Caucasus and the Iranian Plateau. It contains the source belt but is far wider than it, so the label does not isolate the eastern-Mediterranean sector named in standard source descriptions. |
Why not "More than one of the above": the three names are nested rather than independent. The Mediterranean coastal area lies inside Western Asia, and part of it is the shore of Asia Minor. A composite option would be right only if two of the listed places each answered the stem in their own right; here the stem asks for the place of origin, and only the most precise of the three nested names — the Mediterranean coastal belt — actually locates it. The wider labels merely contain it.
Result: the place of origin of the western disturbances active over north-western India in winter is the Mediterranean coastal area of Western Asia.