Jetstream

noun (countable)

/ˈdʒɛtstriːm/

A narrow band of fast-moving upper-tropospheric wind, driven by strong horizontal temperature gradients (baroclinicity) between adjacent air masses. The two primary jet streams, the polar jet and the subtropical jet, meander latitudinally through Rossby waves, steering mid-latitude weather systems. For UPSC, the Western Disturbances that bring winter rain to northwest India travel along the subtropical jet stream.

✍️ Usage in a UPSC answer

The seasonal northward shift of the subtropical jet stream is linked with the onset of the southwest monsoon.

Synonyms

upper-level jettropospheric jetwind maximumaerial river (informal)polar front jet

Antonyms

surface windland breezesea breezedoldrumsequatorial calm

🌱 Word Family

jet stream (noun), jetstream (noun, variant), jet-stream axis (compound noun), polar jet (compound noun), subtropical jet (compound noun)

🔡 Root

English jet (a fast stream) + stream

📜 Etymology

German meteorologist Seilkopf (1939) is credited with the German term for it. The word derives from jet (a forceful stream, from French jeter = to throw) combined with stream.

🧠 Memory Hook

JET stream = a JET PLANE's highway in the sky. UPSC tip: the jet stream's seasonal migration is the 'on/off switch' for India's monsoon: when it jumps north over the Himalayas, the monsoon floods in from the south.

🌍 Geography 📖 Seen in: Plate Tectonics and Volcanism…

Relevant across:GS1 · History, Geography & Society

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