At what latitude does the easterly jet stream blow over peninsular India during the summer months?
- (a)30°N
- (b)24°N
- (c)28°N
- (d)14°N
Answer
Why
Correct — D. In the summer months the tropical easterly jet sits over peninsular India at about 14°N, blowing from east to west high in the troposphere.
It can only appear once the sub-tropical westerly jet has withdrawn north of the Himalayas and the upper-air circulation over India reverses.
That reversal is one of the conditions tied to the burst of the south-west monsoon.
14°N is the latitude the standard textbook gives — option (d).
Why the others are wrong
- (a)30°N — 27°-30°N is the belt of the sub-tropical westerly jet over India. That is a different jet, and it is absent over India in summer.
- (b)24°N — 24°N runs near the Tropic of Cancer across central India, north of the peninsular belt where the summer easterly jet is placed.
- (c)28°N — 28°N also falls inside the 27°-30°N westerly-jet belt over northern India, far from the peninsula the question names.
Concept
Jet streams are narrow ribbons of very fast wind in the upper troposphere, and two of them matter for India.
The sub-tropical westerly jet blows south of the Himalayas at roughly 27°-30°N for most of the year, steering in the western disturbances that give north-west India its winter rain.
In summer that jet shifts north of the Tibetan plateau, and the tropical easterly jet takes its place over peninsular India at about 14°N.
The easterly jet migrates through the season and different texts quote slightly different latitudes for different months. SSC follows the textbook figure of 14°N for the summer months.
Key facts
- The tropical easterly jet blows over peninsular India at about 14°N during the summer months.
- The sub-tropical westerly jet lies over India at roughly 27°-30°N, south of the Himalayas, and is absent over India in summer.
- Western disturbances, which bring winter rain to north-west India, are steered in by the westerly jet.
Study next
Common traps
- Mixing the two jets — the westerly is the year-round system at 27°-30°N, the easterly the summer system at 14°N.
- Assuming a latitude near the Tropic of Cancer must be right because the question says peninsular India.
SSC asks jet streams as a one-line latitude or direction fact, or pairs the westerly jet with western disturbances in a cause-and-effect statement.
The same climate chapter supplies GA Q.1 of this shift, on the Loo.
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