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Welcome back to the third lesson on geography here we are going to see about climate of india geography IAS/UPSC lecture which will be helpful for your preparations with climate of India geography UPSC/IAS
Climate of India
In a country like India which has different geographical structures that varies in region to region we have varied climatic conditions.
India has very hot and very cold regions; as well as regions with very heavy rainfall and very scanty rainfall
Climatic Seasons of India
The South west monsoon controls the agriculture of India, which is the main occupation of the people.
Distribution of Rainfall in India
The rainfall in India is seasonal, uncertain and unevenly distributed
Major factors affecting Indian Climate
Northward shifting of the Westerly Jet (north of himalayas)
Northward shifting of the ITCZ.
S-E trade winds from S. hemisphere cross the equator and turn right due to coriolis force.
Latitudinal Extent
Southern Seas
Northern Mountains
El - Nino
La - Nina
Westerlies in Northern part of India from Mediterranean (in winters)
Easterlies due to Heating of Tibetan Plateau
Jet streams
Indian Monsoon Features
Monsoon is seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea
The southwest monsoon brings rains towards the end of summer as the high pressure built in the Indian Ocean pushes the wind masses towards the low pressure formed on land
Temperature Gradient → It’s the temperature variation between the sea and the landmass
Summer Monsoon in India (SW Monsoon)
• Originates due to Northward shift of ITCZ → SE trade winds cross equator → Deflect & enter into India as SW Monsoon
• Easterly Jet Stream / SE Monsoon / BOB Monsoon → Due to differential heating of Tibetian plateau & Himalayan region BOB
Initiation of Summer Monsoon
• The southwest monsoon typically breaks over Indian Territory by around 25 May, when it lashes the Andaman and Nicobar Islands in the Bay of Bengal
• It strikes the Indian mainland around 1 June near the Malabar Coast of Kerala
• By 9 June, it reaches Mumbai; it appears over Delhi by 29 June
Withdrawal of Summer Monsoon
• Monsoon clouds begin retreating from North India by the end of August; it withdraws from Mumbai by 5 October
• As India further cools during September, the southwest monsoon weakens. By the end of November, it leaves the country
Arabian Sea Branch
• Strikes WGs + Move parallel to Aravallis & Strike Himalayas
• Rainfall at WGs & Coastal Regions + Northern Plains
• Strikes at Western Ghats; and gives rainfall to the western most regions
• While rain shadow interiors, the Deccan plateau receive very less rainfall.
Bay of Bengal Branch
• Moves parallel with the Eastern Ghats and produce very less rainfall until it strikes at NE.
• Bifurcate at Meghalaya hills & move parallel to Himalaya
• One branch provide rainfall to NE India region
Retreating or NE Monsoon
• Around September, with the sun fast retreating south, the northern land mass of the Indian subcontinent cool off rapidly Indian ocean
Winter Rainfall in South India
• While travelling towards the Indian Ocean, the dry cold wind picks up some moisture from the Bay of Bengal and pours it over peninsular India and parts of Sri Lanka
• Cities like Madras, which get less rain from the Southwest Monsoon, receive rain from this Monsoon.
Jet Streams
• Jet streams are currents of air high above the Earth
• They at altitudes of about 8 to 15 kilometers, located near tropopause
• The major jet streams on Earth are westerly winds (flowing west to east)
• Flow at very high speeds → 120 kmph in winters and 50 kmph in summers
• Jet streams are caused by a combination of a planet’s rotation on its axis and atmospheric heating
Sub-tropical jet stream
• They prevail over the lower latitudes of westerlies.
• It is produced by the rotation of earth and its spherical shape.
• The air over equator has the highest velocity (Coriolis effect)
Sub-Tropical Westerly Jet
• Winter - entirely south of Himalayas - over north India
• Major cause of western disturbance
• STWJ maintain the High pressure over north India
• Hence no Monsoon in winters
• During summers it flows to the north of Himalayas
• Hence low pressure over north India & monsoon
Mid-latitude or polar front jet stream
• It is more variable and is produced by a temperature difference
• In summers its position shifts towards poles and in winters towards equator
Негізгі бет INDIAN GEOGRAPHY : Indian Climate Part 1
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