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Glossary Terms
| Term (EN) | Definition | Exam Relevance |
|---|---|---|
| Köppen Classification | Empirical climate classification using temp/rainfall thresholds; 5 major zones (A–E); devised by Wladimir Köppen | Rajasthan has 4 zones: BWhw, BSh, Cwg, Aw |
| BWhw | Hot desert climate; annual rainfall <25 cm; extreme temp range | Jaisalmer, Barmer — driest zone |
| BSh | Hot steppe (semi-arid); 25–50 cm; transitional between desert and humid | Jodhpur, Nagaur, Churu belt |
| Cwg | Humid subtropical with monsoon; hottest month before rainy season (g=Ganges type) | Jaipur, Alwar, Bharatpur — agricultural heartland |
| Loo | Hot, dry, dusty westerly wind; May–June; 45–50°C; causes heat stroke | Annual exam question; Rajasthan-specific wind |
| Mawat / Mahawat | Winter rainfall from Western Disturbances; critical for rabi crops in northern Rajasthan | PYQ 2023; rabi crop connection |
| Western Disturbance | Extratropical low-pressure system from Mediterranean; travels eastward; brings winter rainfall | PYQ staple; origin + effect = exam answer |
| Continental Climate | Extreme temp range (hot summer, cold winter); low humidity; inland from moderating sea | Explains Churu paradox |
| Drought | Rainfall deficiency causing water scarcity; Rajasthan experiences in 3/10 years on average | Tier 1 climate concern; SDRF link |
| Chhappaniya Akal | Great Famine of 1899–1900 (VS 1956); worst recorded drought-famine in Rajputana | Historical context for climate vulnerability |
| Inter-Tropical Convergence Zone (ITCZ) | Low-pressure belt where NE and SE trade winds converge; controls monsoon position | Break monsoon explained by ITCZ shifting north |
| Arid Zone Research | CAZRI (Central Arid Zone Research Institute) in Jodhpur — research on desertification, drought-resistant crops | Policy institution for Thar Desert |
| Rain Shadow | Leeward side of a mountain receives reduced rainfall; Aravalli creates rain shadow for western Rajasthan | Core concept explaining E-W gradient |
| Desertification | Degradation of arid/semi-arid land; loss of vegetation and topsoil; expanding Thar Desert | Climate change impact on Rajasthan |
| Coefficient of Variation (CV) | Statistical measure of rainfall variability; >40% in Thar (extremely unreliable); ~20% India average | Quantifies drought risk scientifically |
| Isohyet | Line on a map connecting points of equal rainfall; used to demarcate arid/semi-arid zones in Rajasthan | Map-based questions on rainfall distribution |
| Continentality | Climatic effect of large land masses far from the sea; large diurnal and seasonal temperature range; highest in Churu (~47°C day, near-freezing nights) | Explains temperature extremes in Rajasthan |
| Monsoon Trough | Low-pressure axis extending from Pakistan to the Bay of Bengal; its northward shift weakens SW monsoon over Rajasthan (break monsoon) | Mechanism behind monsoon breaks |
| Aravalli Rain Shadow | SW monsoon is parallel to Aravalli range (not perpendicular), so the range gives minimal orographic lift; western Rajasthan remains arid | Core physical geography concept |
| Thermal Low | Low-pressure zone formed over land due to intense surface heating in summer; drives pre-monsoon dust storms (andhi) in Rajasthan | Pre-monsoon weather system |
| Frost | Near-freezing temperatures in Dec–Jan damaging winter crops; most severe in northern and eastern Rajasthan | Agricultural meteorology; rabi crop risk |
Topic 84 of 138 | Paper II, Unit 3 — Earth Science / Geography & Geology | Generated: 2026-04-06