Revision note: Climate, Soils and Natural Vegetation

• SW Monsoon June–Sept brings ~75% of the rainfall; Tamil Nadu gets its rain in Oct–Dec
• Black soil = cotton, moisture retention; laterite = leaching
• Tropical deciduous = most widespread forest

Indian Monsoon – Simple Explanation

Why India gets most of its rain between June and September.

Basic idea

In summer the land heats faster than the sea. A low-pressure area forms over north-west India, and moist winds from the Indian Ocean flow in – the South-West Monsoon (June–September).

Key factors

• Differential heating of land and sea
• Shift of the ITCZ (Inter-Tropical Convergence Zone) northwards
• Tibetan Plateau heating and the Tropical Easterly Jet
• El Niño usually weakens the monsoon; positive IOD (Indian Ocean Dipole) usually helps it

Two branches

• Arabian Sea branch – heavy rain on the Western Ghats
• Bay of Bengal branch – rain in the North-East; Mawsynram/Cherrapunji are among the wettest places