Climate

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Solutions, questions, answers, and notes of chapter 6: Climate which is a part of social science class 9 syllabus of students studying under the Nagaland Board of School Education. However, these notes should be used only for references and additions/modifications should be made as per the requirements.

INTRODUCTION: Climate is the typical weather conditions of an area over a long period of more than thirty to thirty-five years. The climate of a place influences its flora (plants) and fauna (animals). It accounts for environmental diversity. It patterns the livelihood of the people.

Climate is the long-term effect of the Sun’s radiation on the rotating Earth’s surface and atmosphere. It can be understood most easily in terms of annual or seasonal averages of temperature and precipitation. Because of the unusual topography and geographical position of India, climatic conditions are widely diversified, both on a regional as well as a seasonal basis. This diversity is in the range of extremes – from tropical to temperate zones. The temperature extremes are confined largely to the slopes of the Himalayas. Except in the more mountainous regions, the rest of India has a uniformly tropical climate. Seasonal variations, resulting from the southwestern and northeastern monsoons profoundly influence temperature, humidity and precipitation throughout the subcontinent.

The climate of a country is mainly based on the range of its temperature, rainfall, atmospheric pressure and direction of winds.

I. Choose the correct answer.

1. The direction of the monsoon wind in summer is

Answer: (c) North-east

2. Which of the following is not a part of Indian season

Answer: (c) Freezing season

3. The period of transition from hot and rainy to dry and cold season occurs in:

Answer: (c) October-November

4. The highest rainfall in the world is recorded in

Answer: (c) Mawsynram

5. Mango showers fall in which of the following state?

Answer: (a) Kerala-Karnataka

6. The monsoons begin to withdraw from the Northern Plains in the month of

Answer: (c) October

7. In which season the Western Disturbances cause rainfall in western parts of India?

Answer: (b) Winter

II. Very Short Answer Type Questions.

1. Define climate.

Answer: Climate is the typical weather conditions of an area over a long period of more than thirty to thirty-five years. The climate of a place influences its flora (plants) and fauna (animals).

2. What are mango showers?

Answer: When the summer season is about to reach an end, Kerala and Karnataka experience premonsoon showers. These showers are called mango showers.

3. List the elements that affect the climate of India.

Answer: The important elements that affect the climate of India are temperature and precipitation.

4. List the factors that determine the climate of a place.

Answer: The factors that determine the climate of a place are:

(i) Relief and Location
(ii) Altitude
(iii) Distance from the Sea
(iv) Pressure and Winds
(v) Upper-Air Circulation

5. Which part of India experiences a continental type of climate?

Answer: The Northern Plains experiences a continental type of climate.

6. List the four main seasons of India.

Answer: The four main seasons of India are:

(i) Hot Weather Season
(ii) Cold Weather Season
(iii) Advancing Monsoon Season
(iv) Retreating Monsoon Season

7. List the two branches of advancing monsoon.

Answer: The two branches of advancing monsoon are:

(i) The Arabian Sea Branch
(ii) The Bay of Bengal Branch.

III. Short Answer Type Questions.

1. How do Himalayas affect the climate of India?

Answer: The great Himalayan range separates the Indian subcontinent from the rest of Asia, thus preventing the bitter cold winds from Central Asia from entering the country.

2. Give two characteristics of the winter season.

Answer: Two characteristics of the winter season are:

i. Northeast monsoon takes over from the southwest monsoon.
ii. Temperature goes on decreasing towards the north of Tropic of Cancer.

3. What is meant by vagaries of the monsoon?

Answer: The abnormal way the monsoon affects the seasonal pattern of rainfall in India is known as vagaries of monsoon.

4. How have monsoons been a ‘unifying bond’ in India?

Answer: The Himalayas are protective barriers that stop the cold winds from entering the subcontinent. This allows even the areas of northern India which lie on the same latitude to experience uniform high temperature.

5. What is Loo? When and where does it blow?

Answer: A unique feature of the hot weather season in India is the loo. The loo is strong, hot and dry winds that blow during the day in summer.

lV. Long Answer Type Questions.

1. Write about the characteristic features of hot weather season and cold weather season in India.

Answer: The characteristic features of the hot weather season are:

i. This season is marked by dry weather and excessive heat.
ii. The sun shines vertically our Tropic of cancer.
iii. The whole of tropical India, south of Himalayas, experiences very high temperatures.

The characteristic features of the cold weather season are:

i. Northeast monsoon takes over from the southwest monsoon.
ii. Light winter rainfall in northwest India is very useful for the rabi crop, especially wheat.
iii. Temperature goes on decreasing towards the north of Tropic of Cancer.

2. How do south-westerly winds bring rains in India?

Answer: In late summer the low-pressure condition over Northern Plains intensifies. This attracts the trade winds of the Southern Hemisphere. The South-East Trade winds originating over warn sub-tropical areas of southern oceans to cross the equator and blow in a south-westerly direction to India. They are moisture-laden and bring rainfall to India as South-West monsoon.

3. Discuss how the distribution of precipitation differs all over the country.

Answer: India receives an annual rainfall of over 400 cm over parts of the western coast and northeastern India. But in western Rajasthan and parts of Punjab, Haryana and Gujarat only 60 cm rain is recorded. Low rainfall is also recorded in the interiors of the Deccan Plateau in the east of the Sahyadris. Around Leh in Jammu and Kashmir, we can once again observe low precipitation. The rest of India gets moderate rainfall while snowfall is restricted to the Himalayan region.

Due to the vagaries of the monsoon, the annual rainfall is bound to vary from year to year. Regions of low rainfall have high variability. These regions include parts of Rajasthan, Gujarat and the leeward sides of Western Ghats.

4. Discuss features of the ‘Retreating Monsoons’.

Answer: The monsoon trough of low pressure grows weaker by October-November. It is then slowly replaced by high pressure. The monsoon’s outreach is rendered unsustainable and the gradual withdrawal begins. This is known as the ‘retreat of monsoon. By the time October begins the monsoons withdraw from the Northern Plains.

The period of transition from hot and rainy to dry and cold season occurs in the months of October-November. Clear skies and rising temperature are prominent marks of retreating monsoon. During the daytime, the temperature remains high but nights are pleasant and cool

5. Discuss the monsoon season in India.

Answer: The monsoon as a unifying bond is an obvious fact. The seasonal alternation of the wind systems and the associated weather conditions provide a rhythmic cycle of the season. The uncertainties of rain and the uneven distribution are a prominent character of the monsoons. It is evident from the fact that sometimes parts of the country may be facing the fury of floods due to heavy rains, while the other parts may be reeling under severe drought conditions due to scanty rainfall. The most important aspect of Indian rainfall is that it is largely controlled by orography.

6. Explain how upper air circulation operates as a factor influencing the climate of India.

Answer: The higher level of the atmosphere experiences an altogether different pattern of air circulation. These fast blowing winds are called jet streams. The westerly jet the stream gets divided into two streams after it meets a barrier in the Tibetan Highlands. The southern branch blows in an eastward direction south of the Himalayas. It has a great influence on winter in India. During summer the westerly jet stream moves northwards. Later on an easterly jet stream takes its place to flow over northern India. Tropical depressions are brought into India by an easterly jet stream and low-pressure region over land. These depressions aid in the distribution of monsoon rainfall over the whole of India.

7. Why is the western part of Rajasthan arid in spite of the Aravalli Hills? [HOTS]

Answer: The western part of Rajasthan is arid in spite of the Aravali Hills because of the following reasons.

(i) The Aravallis system is unable to prevent the south-western summer monsoon winds and hence, western Rajasthan remains practically dry, while the southern parts do get some rainfall.
(ii) This western part lies at a great distance from the Bay of Bengal, and therefore, the Bay of Bengal monsoon becomes dry and lose most of its moisture by the time it reaches Rajasthan.
(iii) This area is also far away from the Himalayan region, and therefore, it does not come under the influence of monsoon giving rain and remain rainless.

8. Why Shillong has more rainfall than Kolkata? [HOTS]

Answer: Shillong is stationed at a higher altitude comparing to Kolkata, and thus due to the presence of the hills, the Bay of Bengal branch of the southwest monsoon gets obstructed. This results in a heavy shower on Shillong. Kolkata, which is situated to the west of Shillong, receives less rainfall because the rainfall decreases from east to west in North India.

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