GS1 › Indian Physical and Economic Geography

Revision note: The Indian Monsoon: Mechanism, Seasons and Variability

  • 70–75% of rain in SW monsoon (Jun–Sep); onset Kerala ~1 Jun, covers India ~8 Jul
  • Mechanism: ITCZ shift, Coriolis, Tibetan heating, westerly jet moves north, tropical easterly jet, Somali jet
  • El Niño weakens; La Niña and positive IOD strengthen; MJO → active/break spells
  • Branches: Arabian Sea (Ghats, rain-shadow) and Bay (Mawsynram, west along Himalaya)
  • Tamil Nadu: rain mainly from NE monsoon (Oct–Dec)
  • Local storms: mango showers, Kalbaisakhi, loo; western disturbances in winter
  • Normal = 96–104% of LPA (~87 cm)
Revision card summarising The Indian Monsoon: Mechanism, Seasons and Variability
One-page visual summary of the key points to revise.

Source: https://upscprep.in/upsc/gs1/indian-physical-and-economic-geography/the-indian-monsoon-mechanism-seasons-and-variability/ · UPSCPrep.in

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