Discuss the concept of air mass and explain its role in macro-climatic changes.

Theme

T29 Atmosphere, air masses, winds, inversion, deserts & auroras

What UPSC asks in this theme

Questions ask about atmospheric processes: troposphere's role, air masses, temperature inversion, urban heat islands, location of hot deserts, local winds (Loo, Chinook, Foehn), and auroras.

What to cover

• Atmospheric layers and why weather happens in the troposphere
• Air masses and fronts
• Temperature inversion and heat islands
• Trade winds and desert location on western margins
• Local winds and their effects
• Auroras: solar wind and magnetosphere

Writing the answer

• Diagrams help; always add an Indian or world example

These notes are for the whole theme, built from all 6 of its PYQs. UPSC does not publish model answers.