Class 9 Geography Chapter 4 Extra Question Answers - Climate

1) What is Climate?

Answer:  Climate refers to the sum total of weather conditions and variations over a large area for a long period of time (more than 30 years).

2) What does 'weather' mean?

Answer:  Weather refers to the state of the atmosphere over an area at any point in time.

3) What are the elements of weather and climate?

Answer: Temperature, atmospheric pressure, winds, humidity and precipitation are the elements of weather and climate.

4) What is the climate of India?

Answer: India's climate is described as a 'Monsoon Type' climate.

5) What is the variation of temperature in India?

Answer: In some parts of Rajasthan the highest temperature is 50^oC and it is around 45^oC at Drass in Jammu and Kashmir.

6) What is the variation of annual precipitation in India?

Answer:  The annual precipitation is over 400 cms in Meghalaya and less than 10 cms in Ladakh and western Rajasthan.

7) Define the term 'Monsoon'.

Answer: The word monsoon is derived from the Arabic word 'Mausim' which literally means season. Monsoon refers to the seasonal reversal in the wind direction during a year.

8) Why air temperature decreases from the equator to polar?

Answer: Due to the curvature of the earth, the amount of total energy received varies according to latitude. As a result, air temperature decreases from the equator towards the poles.

9) Why hills are cooler during summer and people prefer to go to hill stations?

Answer: As one goes from the surface of the earth to higher altitudes, the atmosphere becomes less dense and temperature decreases. 

10) What does the term 'Sentimentality' mean?

Answer: As the distance from the sea increases its moderating influence decreases and the people experience extreme weather conditions. This condition is known as sentimentality, i.e. very hot during summers and very cold during winters. 

11) Which tropic passes just from the centre of India?

Answer: Tropic of Cancer. 

12) Which surface winds are blowing from India?

Answer: India lies in the regions of northeasterly winds. 

13) What is Coriolis force?

Answer: It is an apparent force caused by the earth's rotation. Coriolis force is responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere.

14) What do you know about 'South-Western Monsoon winds?

Answer: Air moves from the high-pressure area over the southern Indian ocean, in a south-easterly direction, crosses the equator, and turns right towards the low-pressure areas over the Indian subcontinent. These are known as South- West Monsoon Winds.

15) What are Jet Streams?

Answer: Jet streams are fast blowing winds moving in the upper air atmosphere.

16) What are subtropical westerly Jet streams?

Answer: The Jet streams are located approximately over 27^o to 30^o North Latitude, therefore they are known as subtropical westerly Jet streams. 

17) In which parts of India subtropical westerly Jet streams blow?

Answer: Over India, these jet streams blow south of the Himalayas, all throughout the year except in summers. They are responsible for the western cyclonic disturbances in the north and north-western parts. 

18) What are tropical easterly Jet streams?

Answer: An easterly Jet stream called the tropical easterly Jet streams blow over peninsular India, approximately are 14^oN during the summer month

19) What are Western cyclonic disturbances?

Answer: The Western cyclonic disturbances are weather phenomena of the winter months brought in by the westerly flow from the Mediterranean region. 

20) When does tropical cyclone occur in India?

Answer: Tropical cyclones occur during the monsoon as well as in October. These cyclones originate in the Bay of Bengal, hit the eastern coast of India and cause heavy rains causing damage to life and property. 

21) Who noticed the phenomena of the monsoons in India?

Answer: The sailors who came to India in historic times were one of the first to have noticed the phenomenon of monsoon. They benefitted from the reversal of the wind system as they came by sailing ships at the mercy of the winds.

22) How differential heating and cooling of land and water help in understanding the mechanism of the monsoon?

Answer: Differential heating and cooling of land and water create a low pressure on the land of India while the seas around experience comparatively high pressure leading to the shifting of winds from south to north.

23) What do you understand by ITCZ?

Answer: It means Inter-Tropical Convergence Zone. It is a broad trough of low pressure in equatorial latitude. This is where northeast and southeast trade winds converge.

24)  How does the presence of high pressure in the east of Madagascar affect the Indian monsoon?

Answer: The presence of the high-pressure area, east of Madagascar approximately at 20^oS over the Indian Ocean, its intensity and the position of this high-pressure area also affects the Indian monsoon. 

25) What do you understand by the term SO?

Answer: SO means southern oscillation. Normally when the tropical eastern South Pacific ocean experiences high pressure, the tropical eastern Indian ocean experiences low pressure. This periodic change in pressure conditions is known as Southern Oscillation.

26) What is El Nino?

Answer: El Nino is a warm ocean current that flows past the Peruvian coast in place of cold Peruvian current every 2 to 5 years. 

27) What does ENSO Mean?

Answer: ENSO is the combination of El Nino and the southern oscillation. The changes in pressure conditions are connected to El Nino, hence the phenomenon is referred to as ENSO. 

28)  What do you mean by 'Burst of Monsoon'?

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

29) Name the two branches of South-West Monsoons of India.

Answer:(i) Arabian sea Branch (ii) Bay of Bengal Branch 

30) Name the four main seasons of India.

Answer:  Four main seasons of India are:
(i) The cold-weather season
(ii) The hot weather season
(iii) The advancing monsoons
(iv) The retreating monsoons.

31) When do we experience the cold-weather season in India?

Answer:  It begins from mid-November in northern India and stays till February. 

32) What is the average temperature of North India and Coastal plains during winter?

Answer:  The average temperature in coastal areas is between 24^o - 25^oC, while in the northern plains, it ranges between 10^o to 15^o Celsius. 

33) Why winters in India experience a dry season?

Answer: During this season northeast trade winds prevail over the country. Since they blow from land to sea in most part of the country, it is the dry season. 

34) What is 'Mahawat'?

Answer: The total amount of winter rainfall is locally known as 'Mahawat'. 

35) In which months do we experience the hot weather season?

Answer: In the months of March, April, May and June, it is a hot weather season in India. 

36) In which regions of India does 'Elongated low-Pressure Area' develop?

Answer: Towards the end of May an elongated low-pressure area develops in the region extending from the Thar desert in the northwest to Patna and Chotanagpur Plateau in the east and southeast. 

37) What is 'Loo'?

Answer: These are strong gusty, hot dry winds blowing during the day over the north and northwestern India. 

38) What is the effect of 'Dust storms' in India during summers?

Answer: Dust storms are very common during the month of May in northern India. These storms bring temporary relief as they lower the temperature and may bring light rain and cool breeze.

39) What is 'Kaal Baisakhi'?

Answer: Kaal means destruction or calamity brought in the month of Baisakh. It is known as Kaal Baisakhi. It occurs in West Bengal and is pre-monsoon showers. 

40) What are 'Mango-Showers'?

Answer: Mango showers are the pre-monsoon showers taking place on the coast of Kerala and Karnataka. Since they help in the early ripening of mangoes, they are called Mango showers. 

41) Which region of India receives the highest rainfall in the world?

Answer: Mawsynram in the southern region of Khasi Hills in Meghalaya, receives the highest average rainfall in the world. 

42) What does 'breaks in rainfall' mean?

Answer: It means wet and dry spells of rain. The monsoon rainfall takes place only for a few days at a time, these rainless intervals in between are called "breaks in rainfall". 

43) How do heavy floods occur during monsoons?

Answer: When the axis of rainfall shifts closer to the Himalayas, there are large dry spells in the plains and widespread rain occurs in the mountainous catchment areas of Himalayan rivers. These heavy rains bring devastating floods causing damage to life and property in the plains. 

44) How is monsoon known for its uncertainty?

Answer: Monsoon is known for its uncertainty there are wet spells both and also these spells of rains vary in intensity frequency and duration. 

45) What is 'October Heat'? 

Answer: In the month of October monsoon winds retreat. It is marked by clear skies and a rise in temperature. Owing to the conditions of high temperature and humidity, the weather becomes rather oppressive during the day. This condition is called 'October heat'. 

46) Differentiate between climate and weather.

Answer:

• Climate: It refers to the sum total of the weather conditions and variations over a large area for a long period of time.
• Weather: It refers to the state of the atmosphere over an area at any point in time. The elements of weather and climate are the same. 

47) What type of climate does India have?

Answer:

• India has a 'monsoon type' of climate.
• This type of climate is found mainly in South and Southeast Asia.
• It is called 'monsoonal' since India receives pre-monsoon showers in the month of May, proper monsoon during the hot weather season, winter monsoon due to western disturbances in winter and a little rain when the monsoons retreat. 

48) Why does India have a monsoon type of climate?

Answer:  

• The climate of India is strongly governed by the monsoon winds. Monsoon winds are confined to tropical lands between 20^o North and 20^o South.
• In the Indian subcontinent, the Himalaya's guide the flow of the monsoon winds bunging the whole of the subcontinent under the influence of these winds.
• These winds account for 75% to 90% of annual rainfall from June to September.
• It is influenced by South-West monsoons. Retreating monsoons and North-East monsoons. 

49) How does the latitude affect India's climate?

Answer: 

• The Tropic of Cancer passes almost from the middle of the country.
• Almost half of the country, lying south of the Tropic of Cancer, belongs to the tropical area.
• All the remaining area in the north of the Tropic lies in the sub-tropical area. Therefore, India's climate has characteristics of tropical as well as the sub-tropical type of climate. 

50) How does altitude affect the climate of India?

Answer: 

• India has mountains to the north which have an average height of about 6,000 mts.
• The Himalayas prevent the cold winds from Central Asia, from entering the subcontinent.
• It is due to these mountains that the Indian subcontinent experiences comparatively milder winters as compared to Central Asia. 

51) What is the Coriolis force? Describe its effect briefly on the world climate.

Answer: Coriolis force is an apparent force caused by the Earth's rotation. It is responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere. Under the effect of Coriolis force, the trade winds moving from sub-tropical high-pressure belts to equational low-pressure belts become north-east trade winds in the northern hemisphere and south-east trade winds in the southern hemisphere. As a result, they bring heavy rainfall to the east coast and the west coast remains dry. 

52) What are western cyclonic disturbances?

Answer: 

• Western cyclonic disturbances are a weather phenomenon of the winters. 
• They are brought in by the westerly flow from the Mediterranean region. 
• They usually influence the weather of the north and north-western regions of India. 

53) What are Tropical cyclones?

Answer:

• They occur during the monsoon, as well as in October and November.
• These disturbances affect the eastern coastal regions of India.
• They originate over the Andaman sea and are often very destructive. 

54) Give a brief note on the 'Inter-Tropical Convergence Zone.

Answer: 

• The Inter-Tropical Convergence Zone is a trough of low pressure in equatorial latitudes.
• This is where the northwest and the southeast trade winds converge.
• This convergence zone lies more or less parallel to the equator but moves north or south with the apparent movement of the Sun. 

55) Define Kaal Baisakhi and Mango Showers.

Answer:

• Kaal Baisakhi: It is a calamity for the month of Baisakh. These are thunderstorms associated with violent winds, torrential rains often accompanied by hail. 
• Mango Showers: Towards the close of the summer season, pre-monsoon showers are common especially in Kerala and Karnataka. Since they help in the early ripening of mangoes, they are called Mango Showers. 

56) How is monsoon known for its uncertainties?

Answer: 

• The alternation of dry and wet spells varies in intensity, frequency and duration.
• It may cause heavy floods in one part and drought in the other part.
• It is often irregular in its arrival and retreat. Hence, monsoons affect the farming schedule of millions of farmers all over the country.

57)   What do you understand by October Heat?

Answer: 

• In the month of October, day temperatures are high, nights are cool and pleasant. The land is still moist.
• Owing to the conditions of high temperature and humidity, the weather becomes oppressive during the day.
• This condition is commonly known as October Heat. 

58) Why are Thiruvananthapuram and Shillong rainier in June?

Answer: 

• The monsoons break there with full fury, right in the beginning of June. This month as a whole has good rains.
• The monsoon also strikes these places directly. Their location helps them get the first and full impact of the monsoon currents.

59) Why is July rainier in Mumbai than in Thiruvananthapuram?

Answer: 

• Mumbai is located about 10^o north of Thiruvananthapuram. The monsoon reaches here in the second week of July.
• The first ten days of June are rainy in Mumbai, but July as a whole is very rainy for it.
• The monsoon breaks with full force on June 1 in Thiruvananthapuram. June is rainier here than July. 

60)   Why are South West (S.W.) monsoons less rainy in Chennai?

Answer: 

• Chennai is located on the Coromandel coast. It lies in the rain shadow region of the Arabian Sea branch of S.W. monsoons. 
• It first strikes the western coastal region and is almost exhausted by the time it reaches Chennai.
• The Bay of Bengal branch runs nearly parallel to the Coromandel coast. So, it also fails to give rains to Chennai.
• Besides, offshore dry winds blow over this region in the summers. 

61) Why is Shillong rainier than Kolkata?

Answer:

• The Bay of Bengal branch of S.W. monsoons approaches Shillong about a week before it touches Kolkata. 
• So, the early start of monsoons gives Shillong more rains. Shillong is also located on the 1500-metre high Meghalaya plateau. 
• A sub-branch of the Bay of Bengal branch strikes it directly. 
• Here the Garo, Khasi Hills capture the clouds like a funnel and cause heavy rains, i.e. more than Kolkata.

62) How does Delhi receive more rainfall than Jodhpur?

Answer:  

• Delhi receives more rainfall since it is better located with respect to the arrival of the monsoons and the western disturbances.
• It gets mild rains from both the branches of S.W. monsoons as well as the western disturbances.
• Jodhpur gets rains mainly from the Arabian Sea branch of the monsoon. Thermal heating during the summer also reduces precipitation. Winter is dry in this region. 

63) Why has Leh moderate precipitation almost throughout the year?   

Answer: Leh is also called a cold desert.

•  Leh has moderate precipitation almost throughout the year because of its topographical location.
• It lies on the landlocked high Ladakh plateau, beyond the Himalayas.
• The local precipitation is very less, but it is well distributed in the form of rains in summers and snowfall in winters.       

64) What are the variations in Indian temperature?

Answer: 

• In summer, the maximum temperature goes up to 50^oC in some parts of Rajasthan.
  Whereas it may be around 20^oC in Pahalgam in Jammu and Kashmir.
• The night temperature at Drass in Jammu and Kashmir may be as low as minus 45^oC.
• Thiruvananthapuram, on the other hand, may have a temperature of20^oC.
• In the Thar Desert, the day temperature may rise to 50^oC and drop to 15^oC the same night.
• On the other hand, there is hardly any difference in the day and night temperatures in Andaman and Nicobar islands or in Kerala. 

65) What are the variations in precipitation in India?

Answer: 

• There are variations not only in the form and types of precipitation but also in its amount and seasonal distribution.
• Precipitation is mostly in the form of snowfall in the upper parts of the Himalayas but it rains over the rest of the country.
• The annual precipitation varies from 400 cm in Meghalaya to less than 10 cm in Ladakh and western Rajasthan.
• Most parts of the country receive rainfall from June to September but some parts like the Tamil Nadu coast gets most of its rains during October and November.