FACTORS AFFECTING INDIA’S CLIMATE
FACTORS AFFECTING INDIA’S CLIMATE
Latitude
- The Tropic of Cancer passes through the middle of the country from the Rann of Kuchchh in the west to Mizoram in the east.
- Almost half of the country, lying south of the Tropic of Cancer, belongs to the tropical areas.
- All the remaining area, north of the Tropic, lies in the sub-tropics.
- Therefore, India’s climate has characteristics of tropical as well as subtropical
Altitude
- India has mountains to the north, which have an average height of about 6,000 metres.
- India also has a vast coastal area where the maximum elevation is about 30 meters.
- The Himalayas prevent the cold winds from Central Asia from entering the subcontinent.
- It is because of these mountains that this subcontinent experiences comparatively milder winters as compared to central Asia. FACTORS AFFECTING INDIA’S CLIMATE
Pressure and Winds
- The climate and associated weather conditions in India are governed by the following:
atmospheric conditions: • Pressure and surface winds; • Upper air circulation; and • Western cyclonic disturbances and tropical cyclones.
- India lies in the region of north easterly winds.
- These winds originate from the subtropical high-pressure belt of the northern hemisphere.
- They blow south, get deflected to the right due to the Coriolis force, and move on towards the equatorial low- pressure area. FACTORS AFFECTING INDIA’S CLIMATE
- Generally, these winds carry very little moisture as they originate and blow over land.
- Therefore, they bring little or no rain.
- Hence, India should have been an arid land, but, it is not so
- The pressure and wind conditions over India are unique.
- During winter, there is a high-pressure area north of the Himalayas.
- Cold dry winds blow from this region to the low-pressure areas over the oceans to the south.
- In summer, a low-pressure area develops over interior Asia as well as over northwestern India.
- This causes a complete reversal of the direction of winds during summers.
- Air moves from the high-pressure area over the southern Indian Ocean, in a south-easterly direction, crosses the equator, and turns right towards the low-pressure areas over the Indian subcontinent.
- These are known as the Southwest Monsoon winds.
- These winds blow over the warm oceans, gather moisture and bring widespread rainfall over the mainland of
- The upper air circulation in this region is dominated by a westerly flow.
- An important component of this flow is the jet stream.
- These jet streams are located approximately over 27-30 degrees north latitude, therefore, they are known as sub-tropical westerly jet streams.
- Over India, these jet streams blow south of the Himalayas, all through the year except in summer.
- The western cyclonic disturbances experienced in the north and north-western parts of the country are brought in by this westerly flow.
- In summer, the subtropical westerly jet stream moves north of the Himalayas with the apparent movement of the sun. FACTORS AFFECTING INDIA’S CLIMATE
- An easterly jet stream, called the sub-tropical easterly jet stream blows over peninsular India, approximately over 14°N during the summer months.
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