Intro (Micro Notes Format):
Air mass is a large body of air with uniform temperature, humidity, and pressure characteristics acquired from its source region. It plays a critical role in macro-climatic changes by influencing regional weather patterns and climatic variability.
Concept of Air Mass:
- Covers thousands of sq. km.
- Categorized based on source region:
- Continental (c) – dry;
- Maritime (m) – moist;
- Tropical (T) – warm;
- Polar (P) – cold;
- Arctic/Antarctic (A) – extremely cold.
- Example: mT (Maritime Tropical) – warm and moist air from oceans.
Role in Macro-Climatic Changes:
1. Weather System Development:
- Interaction of air masses forms fronts, leading to cyclones, storms, and rainfall.
- E.g., Nor’easters in North America form due to mT and cP interaction.
2. Monsoon Mechanism:
- Indian monsoon influenced by mT air masses from Indian Ocean.
3. Heatwaves & Cold Waves:
- Movement of cT or cP air masses causes prolonged temperature anomalies.
- E.g., cold waves in North India during winter.
4. Precipitation & Drought Patterns:
- Dominance or absence of moist air masses determines rainfall or drought.
- E.g., blocking of westerlies causes winter drought in North India.
5. Climatic Zones Shaping:
- Long-term air mass influence defines climatic types (e.g., Mediterranean, Continental).
Conclusion:
Air masses significantly influence macro-climatic variations by altering temperature, precipitation, and pressure patterns, and are central to understanding global and regional climate systems.
