GEOGRAPHY (IX)-LESSON-4 CLIMATE (QUESTION ANSWERS)

 

GEOGRAPHY (IX)-LESSON-4

CLIMATE

(QUESTION ANSWERS)

____________________________________________________________

NCERT EXERCISE

1. 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: 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: Loo

(iii) Which one of the following causes rainfall during winters in the north-western part of India?

(a) Cyclonic depression

(b) Retreating monsoon

(c) Western disturbances

(d) Southwest monsoon

Answer: Western disturbances

(iv) Monsoon arrives in India approximately in:

(a) Early May

(b) Early July

(c) Early June

(d) Early August

Answer: 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: Warm days and cold nights.

2. Answer the following questions briefly.

(i) What are the factors affecting the climate of India?

Answer: The factors affecting the climate of India are

1. Latitude

2. Altitude

3. Pressure and Winds

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

Answer: The climate of India is described as the ‘monsoon’ type. Monsoon refers to the seasonal reversal in the wind direction during a year.
The monsoon type of climate is characterised by a distinct seasonal pattern. The weather conditions greatly change from one season to the other. These changes are particularly noticeable in the interior parts of the country. The coastal areas do not experience much variation in temperature though there is variation in rainfall pattern.
Four main seasons can be identified in India – the cold weather season, the hot weather season, the advancing monsoon and the retreating monsoon with some regional variations.
The climate of India is strongly influenced by monsoon winds. The duration of the monsoon is between 100- 120 days from early June to mid-September.

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

Answer: The regions experiencing this phenomenon are in the north western part of India. The reason behind this effect is the Thar desert. Moreover, this region does not have an ocean to moderate the temperature.

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

Answer: Southwest monsoon winds are responsible for rainfall along the Malabar Coast.

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

Answer: Jet Streams are a narrow belt of high altitude (above 12,000 m) westerly winds in the troposphere. Their speed varies from about 110 km/h in summer to about 184 km/h in winter. A number of separate jet streams have been identified. The most constant is the mid-latitude and subtropical jet stream. They cause depressions during the monsoon season.

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

Answer: The climate of India is described as the ‘monsoon’ type. Monsoon refers to the seasonal reversal in the wind direction during a year.
There is an alteration of dry and wet spells which vary in intensity, frequency and duration. It called as break in monsoon.

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

Answer: There is a great diversity of climatic condition in India due to different latitude and relief. But these diversities are subdued by the monsoon. It provides a rhythmic cycle of seasons.

1.    The vegetation, animal life and agricultural activities are all revolving around the effects of the monsoon.

2.    The life of the people, their celebration of festivals and other activities all are geared to the monsoon as India is still primarily an agricultural nation.

3.    The monsoon provides the water to set agricultural activities in motion and hence, the arrival of the monsoon is awaited eagerly.

4.    The river valleys which carry this water also unite as single river valley unit.

 

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

Answer: As they move in the direction, the winds lose the moisture content. Hence the reason for the reduction in rainfall.

4. Give reasons as to why.

(i) Seasonal reversal of wind direction takes place over the Indian subcontinent?

Answer:

1. Seasonal change in wind direction due to pressure difference.

2. El-Nino plays a major role.

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

Answer: Rainfall is dependent on the South West Monsoon winds, it rapidly progresses and covers large swathes of the country by July.

(iii) The Tamil Nadu coast receives winter rainfall.

Answer: Most of the country remains dry as wind blow from land towards sea. The only rain occurs in Tamil Nadu and Southern Andhra Pradesh due to these winds picking up moisture from the Bay of Bengal. It is because of North-East monsoon winds.

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

Answer: The Bay of Bengal faces frequent pressure changes.

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

Answer: Because they fall in the rain shadow region of Aravali Mountains.

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

Answer: Although there is an overall unity in the general climatic pattern in India, there are some perceptible regional variations. We will see the variation by taking two elements: -

TEMPERATURE

1.    The temperature in the winter in North-Western mountainous regions can go down to – 45° C (at Drass in Jammu and Kashmir), while it is 22°C in Thiruvananthapuram in Kerala.

2.    Similarly, it can go up to 50°C in summer in some parts of Western Rajasthan and 20°C in Shillong.

3.    In many areas, there is a wide variation between day and night temperatures. In the Thar Desert, the day temperature may rise up to 50°C and drop down to near 15°C the same night. On the other hand, there is hardly any difference in day and night temperatures in the Andaman and Nicobar Islands or in Kerala.

Ø PRECIPITATION

1.    There is a wide variation observed in its amount and seasonal distribution. The annual precipitation varies from over 400 cm in Meghalaya to less than 10 cm in Ladakh and Western Rajasthan.

2.    Precipitation in the form of snowfall occurs only in upper parts of Himalayas, the rest of the country receives rainfall.

3.    Most parts of the country receive rainfall from June to September, but the Tamil Nadu coast gets most of its rain during October and November.

Ø CONCLUSION

1.    By these variations we can see that Coastal regions experience mild temperature compare to the interior regions.

2.    The rainfall also decreases from East to West.

Such differences help to create a variety in lives of people— the food they eat, the clothes they wear, the kind of houses they used for living and so on.

6. Discuss the mechanisms of the monsoon.

Answer: 

(a) The differential heating and cooling of land and water creates low pressure on the landmass of India while the seas around experience comparatively high pressure. 

(b) The shift of the position of Inter Tropical Convergence Zone (ITCZ) in summer, over the Ganga plain (this is the equatorial trough normally positioned about 5°N of the equator. It is also known as the monsoon-trough during the monsoon season). 

(c) The presence of the high-pressure area, east of Madagascar, approximately at 20°S over the Indian Ocean. The intensity and position of this high-pressure area affects the Indian Monsoon. 

(d) The Tibetan plateau gets intensely heated during summer, which results in strong vertical air currents and the formation of low pressure over the plateau at about 9 km above sea level. 

(e) The movement of the westerly jet stream to the north of the Himalayas and the presence of the tropical easterly jet stream over the Indian peninsula during summer.

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

Answer:

1.    The cold weather season begins from mid-November and stays till February in Northern parts of India with December and January as the coldest months.

2.    The temperature decreases from South to North.

3.    Clear sky, low temperature and humidity, and feeble, variable winds are the characteristics of the weather. Frost and snow fall also fall in the high mountainous regions of Himalayas.

4.    Most of the country remains dry as wind blow from land towards sea. The only rain occurs in Tamil Nadu and Southern Andhra Pradesh due to these winds picking up moisture from the Bay of Bengal.

5.    In winter rainfall also occur in Punjab, Haryana, Rajasthan, western up because of western cyclonic disturbance occur in Mediterranean Sea. That is locally known as Mahawat. It is useful for cultivation of the Rabi crops

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

Answer:

§  By mid June, low-pressure area intensifies over the Northern plains and attracts the trade winds. These trade winds originate over the warm tropical ocean in the Southern hemisphere.

§  After crossing equator, these blow in the South-West direction entering peninsula as South-West monsoon.

§  Maximum rainfall due to these winds occurs in North-Eastern India (mainly Meghalaya (Mawsynram-Highest) and Assam) and the windward side of the Western Ghats (Thiruvananthapuram to Mumbai).

§  In spite lying in the rain shadow area, the Deccan Plateau and parts of Madhya Pradesh also receive some amount of rainfall.

§  In the Northern plains precipitation decreases from East to West,

§  Tropical Depression, which form at the head of the Bay of Bengal is another phenomenon, which determines amount and Suration of the monsoon.

 

 

OTHER IMPORTANT QUESTIONS

 1. What is climate?
Answer: The climate refers to the sum total of weather conditions and variations over a large area for a long period of time.

 2. What is weather?
Answer: ‘Weather’ refers to the state of the atmosphere over an area at any point of time.

 3. Name the. elements of weather and climate.
Answer: Temperature, atmospheric pressure, wind, humidity and precipitation.

 4. What does ‘monsoon’ imply?
Answer: The word, ‘monsoon’ comes from the Arabic word’ mausim’ which means season. It implies a seasonal reversal in the wind direction throughout the year.

 5. Which are the rainest months of India?
Answer: June to September

 6. Name the month in which the withdrawl of monsoon begins.
Answer: September

 7. Which region of India receives most of its rainfall in winter?
Answer: Tamil Nadu coast.

 8. Name the two branches of the monsoon.
Answer: The Arabian Sea branch.

                 The Bay of Bengal branch.

 9. What is burst of monsoon?
Answer: Around the time of its arrival, the normal rainfall increases suddenly and continues constantly for several days. This is known as the ‘burst’ of the monsoon.

 10. What mean by the ‘retreating monsoons’?
Answer: During the months of October and November, the temperature in the Northern plains begins to decrease, and because of low temperature, the 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.

 11. With reference to the ‘Cold weather season in India, answer the following .
(i) What is its time period?
(ii) Name the winds which prevail over the country during this season.
Answer:
(i) Mid November to February.
(ii) North-East trade winds.

 12. Name the winds from which the Tamil Nadu coast receive winter rainfall?
Answer. North-East monsoons which reach there after passing over the Bay of Bengal, and picking moisture from there. .

 13. Name two coldest areas in India.
Answer: Dras and Kargil (Temperature – 40°C)

 14. Which is the wettest place in India?
Answer: Mawsynram in the southern ranges of the Khasi hills.

 15. What is a jet stream?
Answer: A jet stream is a fast blowing wind blowing in a narrow zone in the upper atmosphere.

 16. ‘The peninsular region does not have a well defined cold season.’ Give reason.
Answer: Due to the moderating influence of the sea, the peninsular region does not have a well defined cold season.

 17. Name two states where mango showers are common.
Answer: Kerala and Karnataka.

 18. Name two states on the eastern coast which are frequently struck by the tropical cyclones.
Answer: Andhra Pradesh and Tamil Nadu.

 19. What is meant by breaking of monsoon or burst of the monsoon?
Answer: The rain bearing monsoons are extremely strong and violent. Their approach is accompanied by thunder and lightning. This is known as the Wreaking of monsoon.

 20. What is the name given to the climate of India?
Answer: The Monsoon climate.

 21. What is loo?
Answer: It is a local wind which is hot and dry.

 22. Name the wind which prevails over India in winter season?

Answer: North-East trade winds.

 23. Two stations with most equable climate.
Answer: Mumbai and Chennai.

 24. Two stations with most extreme climate.
Answer: Leh and Jodhpur.

 25. Name any two regions which receive over 400 cm of rainfall.
Answer: The Western coast and the North-eastern India receive over 400 cm of rainfall.

 26. Name two stations influenced by the retreating and the North-East monsoons.
Answer: Chennai and Bengaluru.

 27. Two stations receiving winter showers from the western disturbances.
Answer: Amritsar and Delhi.

 28. State two chief characteristics of the Western Disturbances?
Answer: These originate over the east Mediterranean sea.

These cause rain in North India.

SHORT ANSWER TYPE

1.    “ Despite an overall unity in the general pattern of climate of India, there are perceptible regional variations in climatic conditions within the country.” Justify.
Or
“India has diverse climatic conditions”Support this statement by giving examples, each of tempera¬ture and precipitation.
Answer:

The temerature occasionally touches 50°C in the western deserts, and it drops down to as low as -45°C in winter around Leh.

The annual precipitation is less than 10 cm in the north-west Himalayas and the western desert. It exceeds 400 cm in Meghalaya.

Most parts of the country receive rainfall from June to September, but some parts like the Tamil Nadu coast get most of its rain during October and November.

2.    Explain the factors affecting India’s climate. [CBSE 2015]
Answer:

Latitude : The Tropic of Cancer passes through the middle of the country from the Rann of Kuchchh in the west to Mizoram in the east. Almost half of the country, lying south of the Tropic of Cancer, belongs to the tropical area. All the remaining area, north of the Tropic, lies in the sub-tropic. Therefore, India’s climate has characteristics of tropical as well as subtropical climates.

Altitude: India has mountains to the north which have an average height of about 6,000 metres. India also has a.vast coastal area where the maximum elevation i% about 30 metres. The Himalayas prevent the cold winds from Central AsiafrQm entering the subcontinent. It is because of these mountains that this subcontinent experiences comparatively milder winters as compared to central Asia.

Pressure and Winds: The pressure and wind conditions over India are unique. During winter, there is a high-pressure area north of the Himalayas. Cold dry winds blow from this region to the low-pressure areas over the oceans to the south. In summer, a low-pressure area develops over interior Asia as well as over northwestern India. This causes a complete reversal of the direction of winds during summer. 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 the Southwest Monsoon winds. These winds blow over the warm oceans, gather moisture and bring widespread rainfall over the mainland of India.

3.    Mention any three characteristics of the Monsoon’.
Answer: The Monsoons are pulsating in nature.

These are affected by different atmospheric conditions prevailing in the region.

The duration of the monsoon is between 100 – 120 days.

 4. What is “October Heat”?
Answer: The months of October-November form a period of transition from a hot rainy season to dry winter conditions. The retreat of monsoons is marked by clear skies, and rise in temperature. The land is still moist. Owing to the condition of high temperature and humidity, the weather becomes rather oppressive. This is commonly known as ‘October Heat’.

 5. Explain development of Monsoon Trough and its influence over rainfall distribution.
Answer: It is a region of low atmospheric pressure which develops because of excessive heat.

It brings a remarkable change in rainfall pattern.

It is responsible for dry and wet spells of monsoon.

 

LONG ANSWER TYPE

1.    Explain about the advancing monsoon in India.

      i.          Monsoon generally reaches the Southern tip of the peninsula during the first week of June.

   ii.          After striking the Southern tip, it branches into two parts- the Arabian Sea branch and the Bay of Bengal branch; both branches move rapidly.

 iii.          The Arabian Sea branch advances North along the Western Ghats, reaching Mumbai by about 10th of June and soon covers the Saurashtra-Kuchchh and central most part of the Deccan Plateau also.

 iv.          The Bay of Bengal branch reaches Assam in the first week of June and gets deflected towards the West by the mountain ranges, thus giving rainfall to the Ganga plains.

    v.          Both the branches again merge over the North-Western part of the Ganga plains. Delhi receives rainfall from Bay of Bengal branch by the end of June (tentative date is 29th June) and by the first-week of July, monsoon covers Western Uttar Pradesh, Punjab, Haryana and Eastern Rajasthan.