CLIMATE OF INDIA - NOTES

INDIA

(Notes)

e) Why are there great variations in the climate of the Indian Subcontinent? Give three reasons.* THE HIMALAYAN MOUNTAIN CHAIN: It protects Indian subcontinent from cold winds of the

Central Asia. It creates barriers before the S-W Monsoon.

* THE LARGE COAST LINE: South India is a Peninsula and has a large coast line. Peninsular

situation has helped it to enjoy maritime climate.

* JET STREAMS: The aircurrents blowing in upper layer of the atmosphere are known as jet streams.

These help western disturbances to enter into India.

f. What is a jet stream?A jet stream is fast wind in a narrow zone in the upper atmosphere.

g. What are trade winds?Trade winds are strong winds that blow towards the equator from the north-east or south east. They can be defined as Planetary winds blowing constantly from the subtropical high pressure zones towards the equatorial low pressure zones.

h. Give two reasons why the entire Indian sub-continent has the tropical monsoon climate.The climate of the subcontinent is greatly affected by the presence and influence of the Himalayas. It prevents the cold winds of north Asia from blowing into India.

The monsoon winds which are trapped by the Himalayas give the climate of the continent a tropical touch.

i. What is loo?It is a local wind which is hot and dry.

l. What is windward side?The upwind side or the side exposed to the direction from which the wind blows. Windward side always receive more rainfall as compared to leeward side. For example, Mahabaleshwar situated on the western side of the Ghats receive 250 cm of rain fall whereas Pune, receives 70 cm as it is on the leeward side.

j. How do Himalayas act as ‘climate divide’?* It prevents the cold winds of the North Asia from blowing into India.

* It also traps the Monsoon winds in summer and causing them to shed their moisture over huge part of the land located south of it..

k. How is average rainfall calculated?

Total annual rainfall

Average rainfall = ________________________

Number of Months

k. Write two features of tropical climate.*Tropical climate has relatively high temperature throughout the year.

* Dry winters are another important feature of tropical climate.

l. What is retreating monsoon and name any two months associated with them. Normally by what date does the monsoon advance into Kerala?During the months of October and November the temperature in the Northern Plains begins to decrease and because of low temperature pressure starts rising and the low pressure is no longer strong enough to attract the monsoon winds. This results in the retreat of the monsoon.

Normally monsoon advances into Kerala on 1st June.

m. State two features of the monsoon climate.* The monsoon climate comes under the domain of trade wind belt which experiences seasonal shifting.

* Monsoon areas are affected by high and low pressure system due to winter and summer seasons.

n. What is meant by ‘rain shadow’ area or ‘ Leeward Area’? Give two examples of ‘Rain Shadow’ areas in India.Area which gets a little or no rainfall is called the Rain Shadow area or Leeward area. This side is completely opposite to the windward side of the mountain.

· Eastern side of Eastern Ghats

· North west Deccan trap

· Eastern side of Eastern Ghats during the south-west monsoon.

n. What is meany by ‘monsoon’?Monsoon is a season in which there is a complete reversal in the direction of wind, i.e. it begins to blow from sea to land contrary to land to sea.

o. What do you understand by ‘Pre-monsoon period’?The period during which low pressure begins to replace the high pressure due to intense heat in the Northern Plains. This period is said to be ‘Pre-Monsoon period.”

2.a) What type of climate is found in India? Give reason.Tropical monsoonal climate because the greater part of the country lies within the tropics and it is also

influenced by the W.W. and N.E. Monsoons.

b) It is cooler on the mountain slopes than in the plains during summer. Give reason.The temperature decreases with increasing altitude. Hence the mountain slopes being higher are cooler than plains.

c) Mumbai is warmer than Kanpur in December. Give reason.Mumbai is near the coast so it enjoys the equable influence of the sea whereas Kanpur is far away from

the sea, so it does not enjoy the equable climate.

d) Western coastal plains receive more rainfall than the Eastern coastal plains.Western coastal plains receive more rainfall than the Eastern Coastal plains because winds come from South West direction and are obstructed by Western Ghats.

e) Though Mangalore and Mysore are on the same latitude, Mangalore experiences more rainfall than Mysore. Give reason.Mangalore is in the windward side of the Western Ghats whereas Mysore is on the leeward side of the

Western Ghats

f. “Western Rajasthan or Thar Desert receives less rainfall.” Or Arabian Sea branch of S-W monsoon does not shed any moisture in western Rajasthan. Or Inspite of Aravalli Hills, many parts of Rajasthan do not receive much rain. Give two reasons.

‘Western Rajasthan receives less rainfall’ because :

* there is no relief or barrier to obstruct the Arabian sea branch of the monsoons. The Aravalli hills

lie parallel to the direction of the monsoon as such they pass without any obstacles. They are also

lower in height.

· Secondly, the summer temperatures in Thar Desert are so high that monsoons that pass over the

desert get dry.

g. Chennai receives less rain than Thiruvanathapuram although it has more rainy days. Give reason.Chennai receives less rain from northeast monsoons during October-November which is not very strong,

hence gives less rain where as Thiruvanathapuram which is in Kerala receives very heavy rain from South

West Monsoons which are much more powerful.

h. Mangalore and Chennai lie on the same latitude, yet Mangalore receives its rainfall from June to September, Chennai receives most of its rain in November-December. What are the reasons for this difference?Mangalore receives rain from South West Monsoons, which blow from June-September as it lies on the windward side of the Western Ghats where Arabian sea branch of the South-West Monsoon gives heavy rainfall. By the time, the South-west Monsoon descends on the leeward side, very little mositre is left. Hence, Chennai receives a little or no rain during this period.

Chennai receives its rainfall in November – December from the North-East monsoon winds which blow over the Bay of Bengal and meet with the moist wind of the retreating summer monsoon. These winds, further, cross Bay of Bengal and blow on the Tamil Nadu causing heavy rain in coastal region including Chennai.

Hence, Mangalore and Chennai lie on the same latitude, yet Mangalore receives its rainfall from June to September, Chennai receives most of its rain in November-December.

i. Explain why Nainital is cooler than Agra.Nainital is a hill station located at a higher altitude. Since temperature decreases with altitude, it is

cooler as compared to Agra which lies in the interior. It experiences continental type of climate.

j. Punjab receives rain in winter. Explain.

Punjab receives rain in winter by westerly depressions which originate in the Mediterranean sea during

January-February.

k. Hill stations in the South never experience snowfall even when temperature fall to 0 degree C. Give reason.

The hill stations in the south are closer towards the Equator, hence the temperatures even if they touch 0

degree C do not experience snowfall.

l. Jaipur has higher annual range of temperature than Mumbai. Give two reasons.

* Jaipur is far away from the moderating influence of the seas. It is an inland town with extreme type of climate but Mumbai has a marine climate.

* It does not get much rain from south west monsoon because the Aravalli range lies parallel to the

direction of winds.

* Jaipur being located in a desert has a high range of temperature. But Mumbai being located on a coastal plain has a low range of temperature.

j. India has varied climatic conditions. Give reason.

India has varied climatic conditions because of its vastness and varied physiographic divisions.

k. South West Monsoons does not give much rainfall to Chennai. Give reason.

Chennai is located on the Eastern Coast. The South-West Monsoon first strikes the Western Ghats and causes a very heavy rainfall. When these winds reach Chennai or the eastern coast they become dry.

l. Patna gets heavier rainfall than Varanasi. Why?

Amount of rainfall decreases as monsoon winds moves westward. These get drier and drier as the distance from sea increases.

m. “Shillong gets less than 200 cm of rainfall in the year while Cherrapunji receives more than 1250 cm of rainfall. Give reason.

Cherrapunji lies on the foothills of Khasi hills in Meghalaya. They are funnel shaped hills. When the moisture laden monsoon winds enter into these hills they are trapped in these hills, causing heavy rainfall. Shillong, on the other hand, lies in the rain shadow area of the Khasi hills and gets less rainfall.

n. Coramandel coast receive most of its rainfall during winter season. Why?

Because its location is on the windward side of the Eastern Ghats.

o. Fishermen are advised not to venture into the Bay of Bengal during months of Oct-Nov. Why?

It is the season of retreating monsoons when tropical cyclones originate over the Bay of Bengal.

p. Amritsar experiences temperatures around 0 degree in December and around 35 degree C + in May. Why?

Amritsar is situated far from the influence of sea, thus experiencing a continental climate with extremes of temperature.

q. The Malabar coast has less rainy months but more rainfall than the Coramandel coast. Why?

* The Malabar Coast in on the windward side of the Western Ghats, while Coromandel Coast is on the

lower side of the Eastern Ghats during summer monsoon.

* The Malabar Coast is first to get rainfall from south-west, while the Coromandel coast gets rainfall

from north-east winds in winter season.

r. The Himalayas act as a perfect climatic divide.

The Himalayas act as a perfect climatic divide as they separate the Indian subcontinent from rest of Asia. On one hand they prevent the chilly cold winds from central Asia from entering the Subcontinent and force the South-West Monsoon winds for rain on the other.

s. The monsoon is unevenly distributed over India. Why?

The amount of rain received by an area depends on its relief, for example, windward side of the mountain receives more rain while leeward side receives less rain. That is why, the monsoon rain is unevenly distributed over India.

t. India is called the ‘Land of Contrast’.

India is called the ‘Land of Contrast’ due to the Himalayas which separate the Indian subcontinent from the rest of Asia and the Tropic of Cancer which divides the country into two halves – North Temperate and South Tropical Zones. These two factors influence the climate of the regions greatly.

u. Most of the rainfall of the Indian subcontinent is received only in 4 months of the year. Why?

Most of the rainfall in the Indian subcontinent occur during mid-June to mid-October due to the South-West monsoon winds as these winds are very strong and laden with plenty of moisture. These moisture laden winds give torrential rain which lasts for 4 months.

v. Kolkatta receives about 145 cm of rainfall while Lahore gets only 45 cm from the South-West Monsoons.

As the South-West Monsoon winds proceed towards west, moisture content gradually decreases thereby rainfall decreases. That is why Kolkatta receives about 145 cm of rainfall while Lahore gets only 45 cm from the South-West Monsoons.

w. The Indo-Gangetic Plain gets some rainfall in the month of December and January. Give reason.The Indo-Gangetic Plain gets some rainfallin the months of December and January due to Western Disturbances moving eastward from the Mediterranean Sea. These disturbances cross into the Indian subcontinent through the Khyber, Bolan and Gomal Passes and give rain showers to the Indo-Gangetic Plain.

x. Chennai has more rainy season months but less rain than Mumbai. Why?Chennai receives most of the rainfall from the North-East monsoon with less moisture thereby causes less rain while Mumbai receives rainfall from the South-West monsoon laden with plenty moisture thereby causes heavy rain.

y. Hot dust-storm are quite common in Thar desert.

Hot and dry weather of the Thar desert creates low pressure over the area which attracts winds from the surrounding areas causing hot dust-storms.

3.a. Which type of climate is experienced in the Northern Plains of India? State one main characteristics of this type of climate.

Tropical monsoon type of climate is experienced in the Northern Plains of India. This type of climate is

marked by very hot summers and very cold winters .

b) Name a state which is influenced by : i) Mango showers ii) Loo

Mango showers – Kerala

Loo – Punjab

C) Name the region in India which receives rainfall from the Western Disturbances. State the importance of this rainfall.

Plains of north-western India i.e. Punjab and Himachal Pradesh.

The rain is highly beneficial to Rabi crop especially wheat.

D) Name and give the direction of winds that cause snow and rainfall in the northern parts of India during the winter season.

‘Western Disturbances’ cause rain in the northern parts during winter season. These Cyclones originate from the Mediterranean Sea. They travel eastwards across Iran and Pakistan and reach India during winter season. On their way, the moisture content gets augmented from the Caspian Sea in the north and the Persian Gulf in the south and give some rain to Punjab and Haryana.

E) Distinguish between windward and leeward side.

WINDWARD SIDE: That side of the mountain which comes across the striking winds and gets heavy rainfall is called windward side. For example, the western side of the Western Ghats gets heavy rainfall 9 like Mangalore 280 cms) because it is in the windward side.

LEEWARD SIDE: It is the other side of the mountain where winds descend after shedding much of the rainfall. This portion receives very less rainfall. For example, Bangalore gets 50 cms rainfall because it is in the leeward side.

g.. What type of climate is found in India? Give reason. (2)

Tropical monsoonal climate because the greater part of the country lies within the tropics and it is also influenced by the South West and North East Monsoons.

h. Name the four seasons of India.# The Cold weather season – December to February.

# The Hot weathr season – March to May

# Advancing Monsoon Season – June to September

# Retreating Monsoon season – October to November.

i.Name two important features of the Indian Monsoon.* Most of the country gets rain from the Southwest Monsoon

* the rain is unevenly distributed.

* It is erratic and unpredictable.

* It is seasonal mostly coming in rainy season.

* Monsoon rains have great effect on our economy.

j. Name any two states that receive rain in January – February. What causes this rain?

Punjab, Jammu and Kashmir. Western disturbances originating over the Mediterranean sea causes these

states to receive rainfall.

k. Name the state which experiences the longest monsoon season and another state which has the shortest monsoon season.

Kerala experiences the longest monsoon season. Jammu and Kashmir experiences the shortest monsoon season.

l. Name the two states where “Mango showers’ are common.

Kerala and Karnataka.

m. Much of the Central Maharashtra has only light rainfall. Give reason.

Central Maharashtra has equable climate. So it does not attract South West Monsoon winds.

Secondly, it is not a hilly region which can trap the South West Monsoon.

n. Thar is a desert area. Why?

# The soil contains a high proportion of salts and percentage of organic matter is low.

# Thar does not get much rain because the ‘Aravalli Range’ lies parallel to the direction of winds and so

no condensation occurs. So this region gets less than 25 cm of rainfall per annum.

o. “Loo’ blows over northern and north-western India during the summer season. What is the cause of this ‘Loo’. Give reason.

Because of high temperature in this region low pressure conditions prevail which help the ‘Loo’ to blow.

4.a. How will you differentiate between SW monsoon and NE monsoon?

SOUTH WEST MONSOONS (SUMMER)

NORTH EAST MONSOON (WINTER)

1. They blow during the months of June to September.

They blow during the months of December to February.

2. These cause heavy rainfall almost throughout India.

These cause very less rainfall.

3. These monsoon travel from sea to land.

These monsoon travel from land to sea.

4. These are characterized by oppressive heat and

humidity known as ‘October Heat’.

This is very pleasant season with low temperature,

low humidity and clear skies.

5.a. Name a state which receives rainfall from three different sources and name the three sources of rainfall.Punjab is the state which receives rainfall from three different sources and the sources are:

a) Northeast Retreating Monsoon

b) Westerly depressions

c) South West Monsoons or cyclonic disturbances originating in the Meditarranean Sea.

b. Mention any two characteristics of winter rainfall in India.

* Winter rainfall is north-western India is due to western disturbances.

* Tamil Nadu receives fair amount of rainfall from N-E monsoons.

c. i) Name the place in India which receives the heaviest rainfall. - MAWSYNRAM

ii) name the state where the place is located. - MEGHALAYA

iii) name the winds which are responsible for this heavy rainfall.- The South West winds coming from the Bay of Bengal branch.

d) What are ‘Western Disturbances’? Name two areas receiving rains from them. What are its importance ?Western Disturbances are shallow cyclonic depressions originating over Mediterranean sea, disturbing fine

weather conditions in north-western parts of India by little rainfall during winter season.

Punjab and Haryana and Himachal receive rains from the Western Disturbances.

IMPORTANCE: These are highly beneficial to rabi crop especially wheat.

e) Why is it that India gets abundant rainfall and still is a thirsty land?

* All the rain is concentrated during a few months (June – Sep.) of the year.

* Distribution of rainfall is uneven.

* No proper facilities are available to store the rain water.

f. Why is the diurnal range of temperature during summer, greater at Bikaner (Rajasthan) than at

Panjim (Goa)

Bikaner at Rajasthan has very high temperature (45 degree C) due to being located further inland experiences a continental climate or it being an arid region, absence of clouds, the day is hot and night temperatures too low resulting in a great diffence or range.. Whereas Panjim (Goa) is in coastal region, and due to moderating influence of the sea, has lower temperature. (27 degree – 32 degree C)

g. Name any two local winds which blow in India and write briefly about each.

i) Loo – It is the hot and dry wind which blows in the northern plains.

ii) Land breeze – The wind blows in the coastal regions. These blow from land to sea.

h. Write two features of mango showers.

* These are the result of contact between dry and moist air masses.

* These are common towards the close of summer and basically found in Kerala and the coastal areas of

Karnataka.

i. State two differences between tropical cyclones and temperate cyclones.

TEMPERATE CYCLONES

TROPICAL CYCLONES

1

The origin and influence of these cyclones is in the temperate zone due to which they are known as temperate cyclones.

These cyclones originate and travel in the tropical zone and are known as tropical cyclones.

2.

The wind velocity is very low.

The wind velocity is very high.

3.

They are more active in winter season.

They are more active in summer season.

4.

Temperate cyclones are bigger in size.

Tropical cyclones are small in size.

5

Temperate cyclones cause less rain useful for wheat crop.

Tropical cyclones cause heavy rains with more destruction.

j. Name the factors which influence the climate of India or South Asia. Or Why are there great variations in the climate of the Indian subcontinent?

* THE HIMALAYAN MOUNTAIN CHAIN: It protects Indian subcontinent from cold winds of the

Central Asia. It creates barriers before the S-W Monsoon.

* THE LARGE COAST LINE: South India is a Peninsula and has a large coast line. Peninsular

situation has helped it to enjoy maritime climate.

* JET STREAMS: The air currents blowing in upper layer of the atmosphere are known as jet

streams. These help western disturbances to enter into India.

* LOCATION AND VAST EXTENT OF THE COUNTRY: India is a vast country. It is located

between 8 degree 4’ N and 37 degree 6’ latitude and 68 degree 7 ‘ to 97 degree 25’E longitude . India

is divided in almost two equal parts by the Tropic of Cancer.

k. Mention two weather conditions which are associates with the ‘break’ or ‘burst monsoon’. Name two states which are affected by ‘Kal Baisakhi’.

Violent thunder and lightening re associated with ‘break’ or ‘burst’ of monsoons.

Assam and West Bengal are affected by ‘Kal Baisakhi’.

l. What is meant by ‘rain shadow area’? Give two examples of ‘rain shadow’ areas in India.

‘Rain Shadow area’ is an area sheltered by the hills from the prevailing winds and having a lighter rainfall than the windward side of the hills.

i) Bangalore ii) Shillong

m. Name one part of India that receives rainfall both in the winter and summer.

Punjab – In winter, Punjab gets rainfall from western disturbances and in summer from South West monsoons.

n. What is the general direction of prevailing winds over the Indian Sub continent in April – May and in July?

IN April – May – N-E Trade Winds , IN July – South West Monsoon

o. Name the place in India which receives the heaviest rainfall. Name the state and the winds which are

responsible for this heavy rainfall.

Mawsynram receives the heaviest rainfall. It is in Meghalaya. They Bay of Bengal branch of South West monsoon winds are responsible for this heavy rainfall.

p. How are the sources of rainfall in the north-west part of India different from the rainfall experienced on the coastal area of eastern India in winter?

In the North-West part of India winter rainfall is brought by ‘Western Disturbances’ which originate in the Mediterranean sea.

The coastal area of Eastern India gets rainfall from North – East trade winds which picks moisture from the Bay of Bengal.

q. Name the season during which the North East Trade Winds dominate the Indian subcontinent? In which season do the above mentioned winds get completely reversed? Name the four months covered by this season.

The North East trade winds dominate the India subcontinent during cold weather season. (Dec to Feb)

The North East trade winds get completely reversed during summer season. Four months covered by this season are June, July, August and September.

r. Name the region in India which receives rainfall from the Western Disturbances. State the importance of this rainfall.

During the winter season because of low temperature, pressure is sufficiently high in the North-Western part of India. On the Southern India, there is low pressure. Light winds with a low velocity (5 km) begin toblow from North – West to Southern part. The system of pressure and winds is disturbed as a result of the inflow of shallow cyclonic depressions from the West and the North-West which originate from the Mediterranean Sea. These low pressure depressions are called Western Disturbances. Due to Western disturbances, the moisture content of the wind gets augmented from Caspian and Persian Gulf. These cause rainfall in Punjab and Himachal Pradesh.

The rain is highly beneficial to Rabi crop especially wheat.

s. What is meant by ‘the season of retreating monsoon’? Name the months of retreating monsoons. Explain how these winds are different from the north-east Trades?The withdrawal of south-west monsoons in the months of October to November is called the season of retreating monsoon.

These are the same winds of summer which come back due to the migration of the sun. North-east trade winds return between the months of December to February when north-western part becomes cold and winds give rainfall on Tamilnadu coast after collecting moisture from Bay of Bengal.

6. a. What is meant by ‘Kal Baisakhi’?Kal Baisakhi are local thunderstorm experienced in the month of Baisakh (april) in West Bengal.

b. Name two states which receive rain in January and February.

Tamilnadu and Andhra Pradesh, Jammu and Kashmir receive rain in Jan and Feb.

c. What causes the winter rain? How does the winter rain benefit agriculture in the area?

North-Eastern winds while passing over the Bay of Bengal pick up moisture and cause rain on the south-eastern coast of India.

The winter rain is beneficial for rice and millet crops in Tamilnadu and for Rabi crops in Punjab.

d. What is the cause or reason for the winter rain in northern India.

* Northern India receives rainfall due to western disturbances, originated over the Mediterranean Sea.

* In Tamil Nadu the northeast monsoon winds pick up moisture from the Bay of Bengal and bring rain.

e. Under what rainfall conditions are the Tropical Rain forests found?

They are found in those regions having rainfall more than 200 cm.

f. India is considered a subcontintent. Give two reasons.

India is considered a Subcontinent because :

· India is a part of Asia from which it is separated by the Great Himalayas.

· It is a large, relatively self contained land mass forming a part of Asia.

· It has varied vegetation and climate of its own. It has tropical monsoon climate.

g. Which wind is responsible for the rainfall experienced over the greater part of the Subcontinent? During which part of the year is this rainfall experienced? Why does Coromandel coast receive most of its rain during winter?

Wind responsible for the rainfall experienced over the greater part of the subcontinent is South West Arabian Sea branch of the monsoon.

They experience the above rainfall during June-September.

The northeast monsoon winds blow over the Bay of Bengal. Before reaching the Coromandel Coast they become moisture laden and give rain to this area during winter season. (Dec-Jan)

h. What is the general direction of prevailing winds over the Indian subcontinent?

i) in April-May - the direction is north east

ii) In July - the direction is southwest to northeast.

i) Why does the most of central Maharashtra have only light rainfall?

Most of central Maharasthtra has only light rainfall because it lies in the rain shadow area of the Western Ghats.

j. What are there great variations in climate of the Indian subcontinent?There are great variations in the climate due to:

· the vast latitudinal expanse

· the varied topographical features

· size of the land

· distance from the sea.

k. A cricket match at Chennai from Oct 24 to 28 had to be abandoned because of bad weather. As a student of geography provide an explanation for this happening. Ensure that your explanation provides the technical name of this seasonin India, the atmospheric pressure conditions over the Bay of Bengal during this part of the year and the typical rainfall regime experienced in Chennai city.The technical name of the season is ‘the season of retreating monsoon’/’northeast monsoon’.

The atmospheric condition over Bay of Bengal during this season is very unstable causing severe cyclones or it can be a low pressure area too.

The months of October and November are the rainiest months.

l. Name the seasons during which the northeast trade winds dominate the Indian subcontinent. In which season do the above mentioned winds get completely reversed? Name the four months of this season.

The season during which these winds dominate are winter/summer.

During the Southwest Monsoon season, the winds get reversed. The four months are June, July, August and September.

m. Name the state which receives rainfall from three different sources and name the three sources of rainfall.Punjab is the state that receives rainfall from three different sources and the sources are:

· Northeast Retreating Monsoons

· Westerly depressions

· Southwest Monsoons or cyclonic disturbances originating in the Mediterranean Sea.

n. Give two reasons why India is considered a Subcontinent?The two reasons for India being considered a Subcontinent are:-

India is a part of Asia from which it is separated by the great Himalayas

It is a large, relatively self-contained landmass forming a part of Asia.

It has a varied vegetation and climate of its own.