climate of india 1 climatic extremes - temperature 55 o c rajasthan on a hot summer day -50 o c...
TRANSCRIPT
1
CLIMATE OF
INDIA
2CLIMATIC EXTREMES - TEMPERATURE
•55o C• Rajasthan on a hot summer day
•-50o C• Ladakh on a winter dawn
3
CLIMATIC EXTREMES - RAINFALL
•>2500 cm• Mawsynram (Meghalaya)
•<13 cm• Thar desert
4
CLIMATIC EXTREMES – ANNUAL RANGE OF
TEMPERATUTE
•3o C • Malabar Coast
•20o C• Interior India (Delhi)
5
SO, WHAT’S COMMON ?
• The entire sub-continent receives rainfall due to Monsoon winds
6
FACTORS AFFECTING CLIMATE OF INDIA
1. Latitude
2. Physical features
3. Altitude
4. Distance from the Sea
5. Other minor factors
7
INFLUENCE OF LATITUDE
• Tropic of Cancer passes through India• Northern half – Temperate• Southern Half – Torrid
• Yet the sub-continent is said to have a
sub-tropical climate!!!• No striking difference of temperature• Seasonal rainfall due to monsoons
8
INFLUENCE OF RELIEF - HIMALAYAS
• Himalayas• Stop cold winds from north• Help to create HT-LP regime• Pull monsoons• Force monsoons to shed moisture in India
• Arakan Yoma Range• Deflect the monsoons into India
9INFLUENCE OF RELIEF – OTHER FEATURES
• Western Ghats• Uneven rainfall in the peninsula
• Aravallis• Dry climate in Rajasthan
10
INFLUENCE OF ALTITUDE
• Deccan Plateau cooler than Northern Plains in summer
• Snowfall in Himalayas
11
DISTANCE FROM THE SEA
• Equable climate in coastal areas
• Extreme climate in the interior
12
OTHER FACTORS
• Western disturbances• Winter Rainfall in Punjab
• Conditions surrounding the sub-continent• Indian Ocean• Africa
• Jet Streams• Not much known
13
Seasons in India
Summer Rainy Season Retreating Monsoon Season Winter
14
THE INDIAN SUMMER
15
Summer Season - Dateline
March to MaySun directly overhead on equator on
March 21Sun directly overhead on Tropic of Cancer
on June 21
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The Indian Summer - Summary
From March to May (Movement of sun from Equator to Tropic of Cancer)
High temperature, low pressure over the northern plains
Low temperature, slightly high pressure over the Peninsular Plateau
High pressure over Indian Ocean
17
The Indian Summer - Summary
Monsoon winds not drawn into India due to HP over Peninsula
Hot ‘Loo’ in northern plainsKalbaisakhi in West BengalMango Showers in Kerala
THE INDIAN SUMMER
March to May
L P
H P
H P H P
MANGO SHOWER
KALBAISAKHI
LOO
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THE INDIAN MONSOON
20
MONSOON – MEANING
• Refers to a seasonal wind which blows over the Indian sub-continent
• Sea to land in summer
• Land to sea in winter
21
MONSOON – UNIQUE FEATURES
• Brings rains to the sub-continent
• Varies in strength
• Uncertain and Uneven
22
MONSOON - TIMELINE
• June to September• Sun moves from Tropic of Cancer to
Equator• Causes LP in peninsular India
• By August, monsoon spreads all over India
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MONSOON – ARRIVAL TIMES
• Monsoon arrival dates• Western Ghats, NE states – 15th June• North-western India, Eastern Ghats – 1st July• Northern Plains, Central India – 15th July
• Kanyakumari is the first place to receive rainfall
• Kerala is the first state to receive rainfall
THE INDIAN MONSOON
JUNE TO SEP
L P
L P
H P
H P
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MECHANISM OF MONSOONS
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DISTRIBUTION OF RAINFALL
• Areas of Heavy Rainfall (>200 cm)• Windward Side of Western Ghats• Eastern Himalayas• West Bengal
• Areas of Moderately heavy rainfall (100-200 cm)• Deccan Plateau• Middle Ganga Valley• Orissa
27
DISTRIBUTION OF RAINFALL
• Areas of Moderate Rainfall (50-100 cm)• Eastern Ghats• Upper Ganga VAlley• Gujarat, Punjab, Rajasthan
• Areas of Scanty Rainfall (<50 cm)• Western Rajasthan• Northern J & K• Kutch
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Rainfall Distribution Map
of India
29
FEATURES OF INDIAN RAINFALL
• Occurs from June to September
• Distinct Rainy Season
• Erratic and unpredictable
• Unevenly distributed
• Orographic rainfall
• Cyclones and convectional rainfall
30
THE RETREATING MONSOON
31Retreating Monsoon - Meaning
►Strength of monsoon decreases►Extent to which monsoons were able
to reach from June to September decreases
►Direction remains the same►Also called ‘Retreating SW Monsoon’
32
Retreating Monsoon - Causes
►Sun moves from Equator towards Tropic of Capricorn
►Temperatures drop►LP replaced by HP
33Retreating Monsoon - Dateline
►October and November►Monsoon withdrawal dates
Northern Plains – 15th September Western Ghats – 1st October Kolkata – 15th October Kerala – 15th November
34Retreating Monsoon - Summary
►Monsoons decrease in intensity►LP gradually replaced by HP►In the northern plains, it is
oppressively hot – a condition called ‘October Heat’
►Cyclones hit east coast and Bangladesh
►Kerala last state from where monsoons withdraw
THE RETREATING MONSOON
OCT AND NOV
L P
L P
H P H P
36
WINTERS OF INDIA
37
The Indian Winter - Dateline
November to February Sun descends towards Tropic of Capricorn
THE INDIAN WINTER
DEC TO FEB
HP
H P
L P L P
NORTH EAST MONSOON
WESTERN DISTURBANCES
39
WINDS IN WINTER
• Although India lies in Trade Wind Belt,
• Himalayas & Arakan Yoma Ranges do not allow them to come to India
40
WINDS IN WINTER
• HP over Land, LP over Sea
• Winds move from Land to Sea
• Deflected due to Coriolis Effect
• Blow from NE to SW
• Called NE monsoon winds
• Direction coincides with Trade Winds
• SW Monsoon winds ‘reverse’ in direction
41
Summary of Indian Winter
Cool and Pleasant December to February Sun shines in the Southern Hemisphere HP over land; LP over Sea Winds move from Land to Sea (North East
Monsoons) – a phenomenon called ‘Reversal of Winds’
42
Summary of Indian Winter
Western Disturbances come to India Cause cyclonic rainfall in Punjab Move along the foothills of the Himalayas into
the Bay of Bengal NE Monsoons joined by Western Disturbances
cause rainfall in Tamil Nadu (Palni, Javadi and Shevaroy hills)