RAS question
Which climate zone in India, as per Koppen's classification, covers western Rajasthan?
Correct answer: (D) BWh (Hot Desert).
Western Rajasthan falls under the BWh climate zone, meaning hot desert, in Koppen's classification.
Explanation
Western Rajasthan, including the Thar Desert belt, is classified as BWh, or hot desert, in Koppen's scheme. The IMD publication on Rajasthan's climate states that Koppen's broad classification is based on variation in temperature and rainfall, and identifies West Rajasthan as "Tropical desert, Arid; hot (BWh)". It also lists Jaisalmer, Barmer, Jodhpur, Bikaner, Nagaur, Ganganagar and Hanumangarh under this tropical desert, arid and hot climate. Western Rajasthan has arid conditions, a sharp temperature range and very low annual rainfall, while eastern Rajasthan shifts towards the semi-arid BSh steppe type rather than the hot-desert category.
Why the other options are wrong
- (A) Am is the tropical monsoon type associated with the very high-rainfall Western Coast and north-eastern India, not arid western Rajasthan.
- (B) Cwa is humid subtropical and applies to the northern plains such as Uttar Pradesh and Bihar, while IMD classifies West Rajasthan as BWh.
- (C) Aw is tropical savanna and fits much of peninsular India rather than the Thar Desert belt of western Rajasthan.
Concept
Indian climatology in physical geography requires matching Koppen symbols with regional climate zones. RAS frequently covers Rajasthan's desert, semi-arid and monsoon-transition zones because they are basic map-based facts for the state.