Question Q5GS1GS1

Explain the mechanism of the Indian monsoon. What role do El-Nino & La-Nina play in its development over the Indian subcontinent?

Main Body

Indian monsoon is a phenomenon of seasonal reversal of winds blowing from ocean to land.

Mechanism of monsoon:

1Differential heating: of land surface & sea surface causes temperature difference.

2Pressure gradient: Tibetan plateau gets heated quickly. Compared to sea. (Specific heat of sea is high eg. they tend) It creates pressure gradient.

3Wind blowing: from High pressure (Mascarene high) region in Indian Ocean to mainland fields.

Role of El-Nino & La-Nina:

1El-nino is warming of central & eastern pacific ocean

2It shifts monsoons of south west indian ocean winds beneath Eastern side.

3Decrease in Rainfall in Indian Plains & increased rainfall on Peruvian Coast.

8Offshore winds: Winds blow from land to sea in 20-30°N latitude → causes upwelling of cold water on Coastal areas → less rainfall. Preserve of hot desert is due to Combined effect of High pressure, Cold current and Gustoff offshore winds.

Major hot deserts in northern hemisphere are located b/w 20-30°North & on western side of continents. Why?

Hot deserts are overlaid due to many factors ranging from Ocean Currents, latitude, winds e.t.c

20-30°N & orth

This area is a sub-tropical High pressure belt

Descending effect: Air descends which minimizes precipitation.

Horse latitude is very calm region & brings stability.

Examely: Sahara desert, Mojave desert.

Western side:

Cold oceanic currents: keep Cold ocean currents desert the temperature of coastal areavery less evaporation of water vaporless rainfall.

for eg: Peruvian Current made atacama desert

Offshore winds:

Winds blow from land to sea in 20-30°N latitudecauses upwelling of cold water on Coastal areasless rainfall

Presence of hot desert is due to Combined effect of High pressure, Cold current and Gustoff offshore winds.

areavery less evaporation of water vapor => less rainfall.

for eg: Peruvian Current made atacama desert

Offshore winds:

Winds blow from land to sea in 20-30°N latitudecauses upwelling of cold water on Coastal areasless rainfall

Presence of hot desert is due to Combined effect of High pressure, Cold current and Gustoff offshore winds.

354 words14 paragraphs

Diagram

Tibetan plateau pressure differential diagram showing high pressure region and land-sea interaction

Explains basic mechanism clearly
Discusses El-Nino and La-Nina roles
Mentions Tibetan plateau's importance
Includes diagram for visualization
Systematic analysis of desert location factors
Uses specific examples
Explains combined effects clearly
Good use of specific currents and regions
Clear explanation of combined effects
Provides specific geographic examples

Open original scan

Page 13

Topper

Abhishek Singh

Subject & Paper

GS1GS1

Topic

Salient features of World's Physical Geography

Monsoon systems and climate patterns

Mechanism of Indian monsoon and role of El-Nino/La-Nina

Writing Stats

354

Total words

Paragraphs

technical, explanatory

Tone