RAS question
According to Koeppen's climate classification, the western desert region of Rajasthan falls under which climate type?
Correct answer: (B) BWhw — Hot desert (arid).
Under Koppen's climate classification, the western desert region of Rajasthan falls under the BWhw hot desert, or arid, climate type.
Explanation
The western Thar Desert region of Rajasthan is classified as BWhw, the hot desert or dry-arid hot climate, in Koppen's scheme. The Rajasthan Forest Department / Arid Forest Research Institute manual classifies Bwhw as the hot desert type, marked by scorching summer heat, dry winters, very meagre rainfall, and vegetation dominated by thorny shrubs with grasses. Its district distribution includes west Jodhpur, Jaisalmer, Bikaner, Ganganagar, Hanumangarh, and western Churu, which aligns with the core western desert belt. The western desert is not simply 'dry Rajasthan' in general; Koppen assigns that arid desert core to BWhw rather than to the neighbouring semi-arid or monsoon zones.
Why the other options are wrong
- (A) Cwg is the monsoon type with dry winters, found in eastern and south-eastern districts such as parts of Udaipur, Chittorgarh, Kota, Baran, Jaipur, Alwar, Bharatpur, and Dholpur, not in the western desert core.
- (C) Aw is a tropical savannah or humid region associated with southern districts such as southern Udaipur, Dungarpur, Banswara, Pratapgarh, and Jhalawar, so it does not describe Rajasthan's western desert.
- (D) BSh is the hot semi-arid steppe type with rainfall higher than the BWhw desert belt, and it belongs to the adjoining semi-arid belt rather than the core hot desert area.
Concept
RAS often tests Rajasthan's climatic regionalisation under Koppen's classification, especially the distinction between hot desert, semi-arid steppe, monsoon, and tropical savannah zones. Climate type links Rajasthan's physical geography with rainfall, vegetation, agriculture, and desert ecology.