Climate and Vegetation
Overview
- This unit covers the spatial and temporal distribution of weather elements in India, including temperature, pressure, winds, and rainfall.
- Focus on Indian monsoons: mechanism, onset, variability, and climatic types.
- Discusses natural vegetation, forest types, wildlife conservation, and biosphere reserves.
Key Concepts
- Weather vs. Climate: Weather is the momentary state of the atmosphere; climate is the average over a longer period.
- Monsoon: Seasonal reversal of winds, crucial for agriculture in India.
Regional Variations in Climate
- Significant differences in climate across regions despite a broad monsoon type.
- Examples:
- Kerala and Tamil Nadu vs. Uttar Pradesh and Bihar.
- Temperature extremes: 55°C in Rajasthan vs. -45°C in Leh.
Rainfall Distribution
- High Rainfall Areas: >200 cm (Western Ghats, Meghalaya).
- Medium Rainfall Areas: 100-200 cm (southern Gujarat, eastern Madhya Pradesh).
- Low Rainfall Areas: 50-100 cm (Delhi, Punjab).
- Inadequate Rainfall Areas: <50 cm (Andhra Pradesh, Ladakh).
Monsoon Mechanism
- Inter-Tropical Convergence Zone (ITCZ): Low pressure at the equator where trade winds converge, influencing monsoon onset.
- Onset of Monsoon: Begins in Kerala by June 1, spreads to Mumbai and Kolkata by mid-June.
- Break in Monsoon: Dry spells during the rainy season due to various factors.
Seasons in India
- Cold Weather Season (Mid-November to February)
- Hot Weather Season (March to May)
- Southwest Monsoon Season (June to September)
- Retreating Monsoon Season (October to November)
Global Warming and Climate Change
- Climate change is ongoing, influenced by human activities and natural processes.
- Greenhouse Gases: CO2, methane, and others contribute to global warming, affecting sea levels and weather patterns.
Important Local Storms
- Mango Showers: Pre-monsoon showers in Kerala.
- Nor Westers: Thunderstorms in Bengal and Assam.
- Loo: Hot winds in northern plains.
Conclusion
- Understanding climate and vegetation is crucial for agriculture and conservation efforts in India.