AS

Abhishek SharmaAIR 38· 2024

Question Q.13GS1GS1

Give a reasoned account of the distribution of deserts across the earth with the help of relevant examples.

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AnswerStrengthsGapsKeywords

Main Body

Deserts are arid or semi-arid regions receiving (<50 cm) rainfall annually. According to Koppen's classification they are represented as BSW, BSK, BWh, BAK.

Global distribution of deserts:

They mostly lie in Tropical & Warm Temperate regions.

1Along horse latitudes (30°N & 30°S) – Due to Hadley cell circulation and subsiding air leading to adiabatic heating → expansion of humidity capacity → low relative humidity, narrow all.
2Cold currents – They lead to absence of moisture along the coast leading to dry conditions.
e.g. Atacama desertHumboldt current
Namib desertCanary current
Mojave desertCalifornia current

etc.

3Offshore winds – Mainly in tropical regions → N-E trade winds blow offshore to W. side of continents.

Similarly for cold deserts (BSK, BAK)

4Mainly in temperate region – Westerlies blow offshore to Eastern side of continents.

e.g. Gobi desert, Patagonia desert

5Some deserts form as they lie in rain shadow region of mountains.

e.g. Thar desert – Rain shadow of Aravali

PatagoniaRain shadow of Andes

Deserts are home to many tribes and are a useful ecosystem having huge solar energy potential.

188 words10 paragraphs

Diagram

World map showing global distribution of deserts including Mojave, Atacama, Sahara, Arabian, Somali, Kalahari, Gobi, Great Australian Desert, and others labeled on their respective continental locations.

  • Well-structured answer using Koppen's classification system
  • Clear categorization of tropical vs. cold deserts
  • Includes specific mechanisms: Hadley cell circulation, cold currents, offshore winds, rain shadow
  • Good use of global examples with specific desert-current pairs
  • Incorporates world map showing geographic distribution
  • Mentions ecological and resource value of deserts

Open original scan

Page 28

Topper

Abhishek Sharma

AIR 382024

Subject & Paper

GS1GS1

Topic

Salient features of World's Physical Geography

Distribution of Key Natural Resources

Desert Distribution and Climate

Writing Stats

188

Total words

10

Paragraphs

Analytical and systematic

Tone