Uniform Climate: The term “Uniform Climate” is also known as “British Climate.” This type of climate is neither excessively hot nor very cold.
Factors Determining Indian Climate:
Latitude, Distance from the Sea, Elevation, Monsoon Winds, Landform, and Jet Streams:
Latitudes:
- India spans from 8°4’N to 37°6’N latitude, with the Tropic of Cancer (23°30’N) dividing the country into two halves.
- South of the Tropic of Cancer experiences high temperatures year-round with mild winters.
- North of the Tropic of Cancer has a temperate climate, with temperatures exceeding 40°C in summer and dropping near freezing in winter.
Elevation:
- As elevation increases, the temperature drops by 6.5°C for every 1000 meters.
- This is known as the “Normal Lapse Rate.
- “Hill stations like Ooty, Mussoorie, and Shimla are cooler than the plains.
Distance from the Sea:
- Proximity to the sea influences temperature and rainfall.
- Peninsular India, being close to the sea, has a moderate climate with mild winters and stable temperatures throughout the year.
- Central and Northern India experience extreme temperature variations, with hot summers and cold winters due to their distance from the sea.
- Kochi, near the coast, maintains an average annual temperature around 30°C, while New Delhi, far from the coast, often exceeds 40°C.
- Coastal areas have high humidity, leading to significant rainfall.
- Kolkata, near the coast, receives 119 cm of annual rainfall, while Bikaner (Rajasthan), inland, records less than 24 cm.
Monsoon Winds:
- Monsoon winds are the most significant factor influencing India’s climate.
- These winds change direction according to the seasons.
- India experiences the effects of monsoon winds for most of the year.
- In India, the sun’s vertical rays strike in mid-June, although summer ends by late May.
- The onset of the Southwest Monsoon brings down temperatures and causes moderate to heavy rainfall across different regions of India.
- Similarly, Southeast India is influenced by the Northeast Monsoon.
Weather refers to the atmospheric conditions at a specific place, while climate refers to the average weather patterns in a region over approximately 30 to 35 years.
Topography:
- India’s topography significantly impacts climate elements like temperature, atmospheric pressure, wind direction, and rainfall.
- The Himalayas block cold winds from Central Asia, keeping the Indian subcontinent warmer even during the winter.
- As a result, North India experiences a tropical climate.
- During the Southwest Monsoon, the Western Ghats’ western slopes receive heavy rainfall.
- In contrast, large areas of Maharashtra, Karnataka, Telangana, Andhra Pradesh, and Tamil Nadu receive less rainfall as they lie in the rain shadow region or leeward side of the Western Ghats.
- During this season, Mangalore on the west coast receives about 250 cm of rainfall, while Bengaluru, located in the rain shadow region, receives only 50 cm.
Jet Streams:
- Jet streams are fast-moving air currents in the upper layers of the atmosphere.
- According to the Jet Stream Theory, the Subtropical Westerly Jet moves from the vast plains towards the Tibetan Plateau, leading to the formation of the Southwest Monsoon.
- The Lower Jet Streams are also instrumental in the formation and retreat of the Southwest Monsoon, creating low-pressure systems.
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