4. Climate-NCERT Solutions | Exercise Geography Class 9 In English

Q1. Choose the correct answer from the four alternatives given below.
(i) Which one of the following places receives the highest rainfall in the world?
(a) Silchar 
(b) Mawsynram

(c) Cherrapunji

(d) Guwahati

Answer: (b) Mawsynram

(ii) The wind blowing in the northern plains in summers is known as:
(a) Kaal Baisakhi 
(b) Loo

(c) Trade Winds

(d) None of the above

Answer: (b) Loo

(iii) Which one of the following causes rainfall during winters in north-western part of India.
(a) Cyclonic depression 
(b) Retreating monsoon

(c) Western disturbances

(d) Southwest monsoon

Answer: (c) Western disturbances

(iv) Monsoon arrives in India approximately in:

(a) Early May 
(b) Early July

(c) Early June

(d) Early August

Answer: (c) Early June

(v) Which one of the following characterises the cold weather season in India?
(a) Warm days and warm nights
(b) Warm days and cold nights
(c) Cool days and cold nights
(d) Cold days and warm nights

Answer: (b) Warm days and cold nights

Q2. Answer the following questions briefly.
Q(i) What are the controls affecting the climate of India?

Answer: 

(i) Latitude

(ii) Altitudes

(iii) Pressure and Wind

(iv) Distance from sea

(v) Ocean currents

(vi) relief

Q(ii) Why does India have a monsoon type of climate?

Answer: 

There are following the reasons for monsoon type climate in India:

(i) The climate of India is heavily influenced by the monsoon winds. The effect of monsoon lasts between 200 north and 200 in tropical areas.

(ii) Due to the divergent process of warming and cooling of land and water, an area of ​​low pressure is formed over the land part of India, while an area of ​​high pressure is formed over its surrounding seas.

(iii) The position of the inter-tropical convergence zone shifts towards the Gangetic plain during the summer season.

(iv) There is a high pressure area in the Indian Ocean above about 200 south latitude east of Madagascar. The position and intensity of this high pressure area influences the Indian monsoon.

Q(iii) Which part of India does experience the highest diurnal range of temperature and why?

Answer: 

The daily temperature is high in the mountainous part, plateau part and some northern plains of India. This is due to the following reasons:

(i) The Tropic of Cancer passes through this part. About half of the country lies to the south of the Tropic of Cancer, which is a tropical region.

(ii) Due to its distance from the sea, the daily temperature of this region increases significantly during the day while it is at its lowest level at night. Here the daily temperature difference is also high.

(iii) The remaining part to the north of the Tropic of Cancer is sub-tropical. The temperature around this circle is high during the day.

Q(iv) Which winds account for rainfall along the Malabar coast?

Answer: The Malabar Coast is the southern and eastern coast of Kerala, where it receives heavy rainfall due to the south-west monsoon winds.

Q(v) What are Jet streams and how do they affect the climate of India?

Answer: 

Jet streams are the westerly winds blowing in a narrow belt in the troposphere at an altitude of more than 12000 m. It is situated between about 27^० to 30^० north latitudes. That's why they are also called sub-tropical western jet streams.

(i) In India, these jet streams flow in the south of the Himalayas throughout the year except the summer season.

(ii) Due to this westerly flow, western cyclonic disturbances come in the north and western part of the country.

(iii) In summer, along with the apparent motion of the Sun, the sub-tropical westerly jet streams move north of the Himalayas.

Q(vi) Define monsoons. What do you understand by “break” in monsoon?

Answer: 

Monsoon is the change in the direction of wind during a year according to the season.

Monsoon break is a phenomenon in which monsoon rains occur only for a few days at a time. They also have rainless intervals when there is a break in the rain. There are two stages in this, one is when the axis of the trough is above the ground level when it rains and the other when the rain stops. This occurs when the axis moves closer to the Himalayas, then the plains remain dry for a long time. This is what is called the break in monsoon.

Q(vii) Why is the monsoon considered a unifying bond?

Answer: 

(i) Every part of India, whether it is from Jammu and Kashmir to Tamil Nadu or Gujarat to Northeast India, all eagerly wait for the monsoon. This is something related to their life and life.

(ii) Every condition of monsoon like early arrival of monsoon, premature departure, prolonged stay, sudden disappearance etc. affects the life and life of the people here.

(iii) The distribution of rainwater and the agricultural process in India is completely dependent on the monsoon, that is why monsoon is considered to be a unifying bond.

Q3. Why does the rainfall decrease from the east to the west in Northern India.

Answer: 

The following reasons are for the decrease in the amount of rainfall in North-India from east to west.

(i) The distribution of rainfall in India is mainly governed by the size of the country. It depends on the entry and route of the winds.

(ii) The south-west monsoon enters from the Bay of Bengal and brings more rainfall to the north-eastern part of India, it brings with it a large amount of water vapor and moisture. As it moves further north-west, the amount of water vapor and moisture decreases. Due to which rainfall is less in these areas.

Q4. Give reasons as to why.
Q(i) Seasonal reversal of wind direction takes place over the Indian subcontinent?

Answer: 

The following are the reasons for the seasonal change in wind direction in the Indian subcontinent.

(i) Air pressure and wind system differ in different seasons. In winter there is high pressure in the north of the Himalayas. The cold dry air of this region blows over the low pressure ocean area in the south.

(ii) In the summer season, a low pressure area arises over inner Asia and north-east India, due to which the direction of the wind changes completely during the summer days.

(iii) In the rainy season, the air flowing from the high pressure area of ​​the Indian Ocean in the south starts blowing towards the low pressure located on the Indian subcontinent, which is called South West Monsoon Winds. This is the reason that there are seasonal changes in the direction of the wind.

(ii) The bulk of rainfall in India is concentrated over a few months.

Answer:

(i) The main reason for rain in India is the monsoon winds blowing here, which blow only for a few months of the year from June to September.

(ii) In these months, the terrestrial part of India is very hot and the oceanic part is less hot, due to which high pressure is generated over the Indian Ocean and due to the flow of air from this high pressure to the low pressure of the land of this subcontinent It brings with it a lot of water vapor and moisture, which is the main reason for rain in these days.

(iii) The Tamil Nadu coast receives winter rainfall.

Answer: 

Tamil Nadu coast receives winter rainfall from Northeastern trade winds.

Between 100 to 120 days during the monsoon season, some places or topographic points like Tamil Nadu receive a large part of the rainfall during October and November from early June to mid-September. Still, on the other hand, many country regions receive rainfall from June to September.

When the wind flows from the sea to land, it takes up moisture from the sea and brings forth the rainfall in the country’s regions. Due to the geographic location, the East Coast perceives the rainfall as the northeastern trade winds flow from the sea to land in this region.

(iv) The delta region of the eastern coast is frequently struck by cyclones.

Answer: The cyclonic depressions which initiate in the Andaman Sea cross the Eastern coasts of India. Due to this heavy and widespread rainfall is seen in the eastern coasts of India. This is one of the reasons for the delta region of the eastern coast to be frequently struck by cyclones.

(v) Parts of Rajasthan, Gujarat and the leeward side of the Western Ghats are drought-prone.

Answer: The parts of Rajasthan, Gujarat and the leeward side of the Western Ghats fall in the rain shadow area of the Aravalli.  Hence, they are drought prone as they don't receive much of rainfall.

Q5. Describe the regional variations in the climatic conditions of India with the help of suitable examples.

Answer: Though there is an overall unity in general pattern of monsoon, there are still some regional variations in climatic conditions. The two important elements that cause these variations are temperature and rainfall.
For example in summer the temperature is about 50 degrees in Rajasthan and on the same day it is about 20 degrees in Pahalgam of Jammu and Kashmir.
In the same way on a winter night temperature at Drass it may be as low as minus 45 degrees and in Thiruvananthapuram it is 20 degrees.

Q6. Discuss the mechanism of monsoons.

Answer: During summer season as land gets heated up, the air rises and the low-pressure area is created on the land and on the other hand high-pressure area is created in the Indian Ocean. Air moves from high-pressure areas to low-pressure areas. The low-pressure land system attracts south-east trade winds but after crossing equator due to Coriolis force, winds turn right towards the low-pressure areas over the Indian subcontinent. These winds start blowing in a south-westerly direction and enter the Indian peninsula as the southwest monsoon. As it reaches India monsoons are divided into two branches namely - Arabian Sea branch and Bay of Bengal branch.

Q7. Give an account of weather conditions and characteristics of the cold season.

Answer: The cold weather season begins from the November in northern India and stays till February. December and January are the coldest months in the northern part of India.   

(i) The weather is normally marked by clear sky, low temperatures, low humidity and feeble variable winds.   

(ii) Days are warm and nights are cold. Frost is common in the north and higher slopes of the Himalayas experience snowfall.   

(iii) During this season, the north-east trade winds blow from land to sea and hence for most parts of the country it is a dry season. Some amount of rainfall occurs on the Tamil Nadu coast from these winds as they blow there from sea to land.   

(iv) A characteristic feature of the cold weather season over the northern plains is the inflow of cyclonic disturbances from the west and the north-west. The low pressure systems originate over the Mediterranean Sea and Western Asia and move into India along with the westerly flow. They cause the much needed winter rains over the plains and snowfall in the mountains.   

(v) Although, the total amount of winter rainfall locally known as 'Mahawat' is small, it is of immense importance for the cultivation of 'rabi' crops. 

(vi) The peninsular region does not have a well defined cold season.  There is hardly any noticeable change in temperature pattern during winter due to the moderating influence of the sea.  

Q8. Give the characteristics and effects of the monsoon rainfall in India.

Answer: 

Characteristics and effects of the monsoon rainfall in India:  

1. The climate of India is described as the 'monsoon' type. Monsoon refers to the seasonal reversal in the wind direction during the year.  

2. The duration of monsoon is between 100-120 days from early June to mid September.

3. Around the time of its arrival, the normal rainfall increases suddenly and continues constantly for several days. This is known as 'burst' of the monsoon.  

4. The monsoon has a tendency to have 'breaks' that means it has wet and dry spells. Monsoon rains take place only for a few days at a time.  

5. The monsoon is known for its uncertainties.  

Effects of the Monsoon  

1. India has been an agricultural country with more than 50% of its population dependent on agriculture. A large part of the country's agriculture is mainly dependent upon the monsoon rains.    

2. There is great variation in the rainfall received by the different parts of the country, somewhere it leads to floods and its absence in other parts leads to drought like conditions.

3. The Indian landscape, its animal and plant life, the entire agricultural calendar and the life of the people, including their festivities are associated with the monsoon
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