136) Explain, what is monsoon? Name the two branches of monsoon and explain any one.
Answer:Monsoon refers to the seasonal reversal in the wind direction during a year. The two branches of monsoon are
(a) Arabian Sea Branch
(b) Bay of Bengal Branch
Bay of Bengal Branch
(i) This branch of monsoon advances rapidly and arrives in the North-Eastern part of the country. Mawsynram in the Southern ranges of the Khasi hills receives the highest average rainfall in the world.
(ii) The lofty mountains cause the monsoon winds to deflect towards the West over the Ganga plains.
(iii) Delhi generally receives the monsoon showers from the Bay of Bengal branch by the end of the June.
(iv) The Bay of Bengal branch merges with the Arabian Sea branch over the North-Western part of the Ganga plains.
137) Which part of India experiences the highest diurnal range of temperature and why?
Answer:The North-Western part of India comprising the Indian Desert experiences the highest diurnal range of temperature. This is because of the fact that sand (found in ample quantity in this region) gains and loses heat very quickly. As a result of this phenomenon, there is a wide difference between day and night temperatures in this region. The day temperature may rise to 50oC and drop down to near 15oC the same night.
138) What is TI Nino? Explain any two features of it.
Answer: El Nino is a name given to the periodic development of warm ocean current along the coast of Peru as a temporary replacement of the cold Peruvian current. Features of 'El Nino' are as follows
(i) The presence of the EI-Nino' leads to an increase in sea-surface temperatures.
(ii) It weakens the trade winds in the regions and causes heavy rainfall, floods or droughts in different regions of the world.
139) Differentiate between the cold weather season and the hot weather season in India by explaining two distinctive features of each.
Answer: Differences between the cold weather season and the hot weather season are as
Cold Weather Season
Hot Weather Season
Northem India becomes a high pressure region, causing winds blowing outward.
Northem India becomes a low pressure region, causing air circulaton, around it,
Temperatures are low and decreasing from the South to the North.
The global heat belt shifts Northwards, causing high temperatures in North India.
140) Why North-West India receives rainfall in winter? Give any three reasons.
Answer: North-West India receives rainfall in winter because
(i) Cyclonic disturbances occur from the West and the North-West.
(ii) These low-pressure systems, originate over the Mediterranean Sea and Western Asia and move into India, along with Westerly flow.
(iii) They cause winter rains over Punjab, Haryana and Northern Plains.
141) How is the Arabian Sea branch of South-West monsoons responsible for good rainfall in Northern Plains of India? Why doesn't it give rain in Central Peninsula?
Answer:(i) The part of South-West Monsoons which blows over Arabian sea is responsible for high rainfall on the Western coast of India.
(ii) These winds enter through Saurashtra and enter Northern plains. These winds strike the Himalayas and give fairly good rainfall as they have abundant moisture.
(iii) South-West monsoons are perpendicular to the direction of Western Ghats. Thus, they give heavy rainfall on the windward side of the Western Ghats.
(iv) Central Peninsula lies on the leeward side of the Western Ghats. Thus, Arabian Sea branch of South-West monsoon does not reach this region.
142) Define burst of monsoons. Give an account of the climatic conditions of the cold weather season in India,
Answer:When monsoons arrive in India, the normal rainfall increases suddenly and continues constantly for several days. This is called burst of monsoon. Climatic conditions of the cold weather.
(i) Cold weather season prevails from November to February.
(ii) The temperature decreases from South to the North.
(iii) Days are warm and nights are cold.
(iv) The North-East trade winds prevail over the country. From these winds some amount of rainfall occurs on the Tamil Nadu coast.
(v) The weather is marked by clear sky, low temperatures and low humidity and feeble, variable winds.
(vi) Low pressure systems, originate over the Mediterranean Sea and move into India, along with the Westerly flow. They cause the much needed winter rains over the plains and snowfall in the mountains
143) Why are South-West monsoons less rainy in Tamil Nadu? Explain.
Answer:Tamil Nadu happens to be in the rain shadow area (Tamil Nadu is on the leeward side of the Western Ghats which obstructs the South-West monsoon.) The section of Western Ghats bordering Tamil Nadu and Kerala captures the South-West monsoon from the Arabian Sea branch. Therefore, South-West monsoon winds provide less rainfall in Tamil Nadu. This region receives rainfall from retreating monsoon.
144) The climate of India is described as the 'monsoon type'. In Asia, this type of climate is found mainly in the South and the South-East. Despite an overall unity in the general pattern, there are perceptible regional variations in climatic conditions within the country. Temperature and precipitation are two important elements and they vary from place to place and season to season. Read the above passage and answer the following questions (a) How can you say that the climate of India is a Monsoon type? (b) What lesson/values have you learnt from the given passage?
Answer: (a) Indian Peninsula is covered on three sides with the Arabian Sea, Bay of Bengal and Indian Ocean. This is the reason why much rainfall is received by our country. In the rainy season, monsoon winds pick up enough moisture to reach most of the country. Western disturbances cause much needed winter rains. Even in peak summers, rainfall is observed in some areas. Hence, we can say that the climate of India is 'Monsoon type'. (b) From this passage I have learnt, that there is climatic variation throughout the country. Precipitation and temperature are responsible for the difference in climatic conditions.
145) Define 'Kal Baisakhi' and 'Loo'. In which parts of India are they experienced? Or Define Kaal Baishakhi, Mango Showers and Loo.
Answer: Kal Baisakhi These are local thunderstorms associated with violent winds, torrential downpours, often accompanied by hail. Loo These are strong, gusty, hot, dry winds blowing during the day over the North and North-Western India. Sometimes they even continue until late in the evening. Direct exposure to these winds may even prove to be fatal. Mango Showers Towards the close of summer season, pre-monsoon showers are common, especially in Kerala and Karnataka. They help in early ripening of mangoes. These are called as mango showers.
146) Why do the Western Ghats receive more rainfall than the Eastern Ghats? Explain briefly.
Answer:Western Ghats receive more rainfall than the Eastern Ghats because (i) Western Ghats receive rainfall from the Arabian Sea monsoon winds. As these winds blow over warm oceans, they bring abuntant moisture. (ii) The Ghats do not allow the winds to cross over without shedding their moisture on the Western slopes. (iii) When these winds reach the Eastern coast, they are almost dry. (iv) Another branch of South-West monsoon i.e., the Bay of Bengal branch moves parallel to the Eastern coast. In this way, this region is located in an un favourable position with reference of the monsoon winds.
147) "Indian monsoon is said to be a unifying bond for the people of the country." Suppose the monsoon is disturbed for a prolonged period of time. What do you think, how will it affect the country?
Answer:In the following ways it will affect the country
(i) There will be a change in landscape.
(ii) The fauna and flora will be disturbed.
(iii) Due to change in cycle of season, Indian agricultural cycle will be disturbed.
(iv) Many of the festivals like Baisakhi, Pongal, Onam, Bihu, etc will come to an end.
(v) Rivers will run short of water so religious rituals will be disturbed.
(vi) Drinking water will go short.
(vii) River navigation and many of the recreational activities will come to halt.
148) Why the houses in Rajasthan have thick walls and flat roofs?
Answer: In Rajasthan, the weather is very hot and there is less rainfall. Some part of the state is covered with desert. The thick walls of the houses insulate the people against the heat in summer and extreme cold in winter due to the desert. Flat roofs are easier to construct and as there is not much rainfall, water will not collect on the rooftops.
149) Why is it that the houses in the Tarai region and in Goa and Mangalore have sloping roofs?
Answer: The houses in the Tarai region and in Goa and Mangalore have sloping roofs because they get heavy rain during the monsoon season. When there are sloping roofs, the rain water can easily flow off towards the ground or to a receptive unit where water is collected instead of collecting on the rooftop.
150) Explain any four features of advancing monsoon with reference to India.
Answer: These are any four features of advancing monsoon (i) Monsoon has two branches. The Arabian Sea branch reaches Mumbai in the second week of June. By mid-June, it reaches Gujarat and Central India. (ii) The Bay of Bengal branch reaches Assam in the first week of June. Due to lofty mountains, it deflects towards the West over the Ganga plains. (iii) The two branches merge over the North-Western part of Ganga plains. (iv) By the first week of July, Western UP, Punjab, Haryana and Eastern Rajasthan receive the monsoon.
151) Where in Mawsynram located? Why does Mawsynram receive the highest amount of rainfall?
Answer: Mawsynram is located in the Southern ranges of the Khasi hills at a height of 1500 m above the sea level. It receives the highest (annual rainfall 1140 cm) rainfall of the world. Mawsynram receives the highest amount of rainfall because
(i) This place is enclosed by hills on three sides.
(ii) The relief features give this place funnel shaped location.
(iii) The Bay of Bengal monsoon is trapped in these hills. These winds try to get out of it, but are forced to pour down there.
152) Why is it said that "Monsoon wind is known for its uncertainties"? Explain any three reasons.
Answer: Monsoon wind is known for its uncertainties because
(i) The movement of low pressure trough controls the spatial distribution of rainfall.
(ii) The alternation of wet and dry spells varies in intensity, frequency and duration.
(iii) It sometime causes heavy floods in one part, it may be responsible for drought in other.
(iv) It is often irregular in its arrival and retreat.
153) Distinguish between the South-West Monsoon and North-East Monsoon.
Answer: Differences between the South-West monsoon and North-East monsoon are as
This season is from June to September
This seasons starts from December and ends in February.
It does not rain continuously. There are rainless intervals in this season.
It does not possess any rainless intervals.
It blows in India as the Arabian Sea branch is due to this type of monsoon.
Minor portion of the annual rainfall in India is due to this of monsoon.
(a) The rainiest month of the year is July. The rainfall in this month is 19.3 cm.
(b) The annual range of temperature is 33.3oC -l4.4oC = 18.9oC
(c) The hottest month of the year in June and the temperature is 33.3oC.
154) Study the following climatic data and answer the questions that follow.
Rainfall in (cm)
(a) Name the rainiest month of the year. How much is the rainfall in this month? (b) What is the annual range of temperature here? (c) Name the hottest month and write the temperature.
155) "You have visited a place as a leader of your school team. The Principal has asked you to make a report on the climate of the placed To conclude about the climate which factros would you take into consideration?
Answer: The following factors can be taken into consideration
(i) Latitude of the place,
(ii) Distance from the sea.
(iii) Alritude of the place.
(vi) Precipitation received at the place,
(v) Relief features of the place.
(a) The annual range of temperature is the difference between the highest and the lowest temperatures recorded in the given year. The highest temperature recorded = 26.7oC The lowest temperature recorded = 10.9o C Annual range of temperature = 26.7o C -10.9o C = 15.8o C
(b) (i) The month that received the lowest rainfall is January,
(ii) The rainfall in January was 7mm.
156) Study the climate data of a station given below and answer the following questions.
Temperature in oC
Rainfall in (cm)
(a) Calculate the annual range of temperature of this station. (b) Which month receives less rainfall and how much?
Answer: Houses in Assam are built on stilts because the state receives abundant rainfall due to which there are chances of floods. In case of flood the water might get inside the houses, if the houses are built on ground level, so in order to avoid flooding of houses, houses are built on stilts and above the ground level.
157) Why houses in Assam are built on stilts?
Answer: Most of the worlds deserts are located in the Western margins of continents in the subtropics because the prevailing winds in the tropics are tropical easterly winds. The tropical easterly winds become dry by the time they reach the Western margins of the continents and so they bring no rainfall. Thus, the region becomes devoid of moisture which causes dry conditions leading to formation of deserts.
158) A recent newspaper report states deficient rains have not only taken a toll on fruit and agriculture crops, but lesser water in the streams has impacted fish breeding also, forcing the authorities to extend the no fishing ban for another fifteen days. Being the only source of livelihood for about 4000 fishermen families, the spokesman said that rains were essential for inducement of fish breeding and a further delay in monsoon would likely result in failure of breeding. Each year during fish breeding season, the State Government bans fishing activity by announcing close season across the state so that spawning and breeding are not affected during this time'. Although the government has taken one step to preserve the livelihood of the fishermen, it is still not enough. Read the above passage and answer the following questions Can you suggest what other steps could have been taken to help the fishermen, including steps before the beginning of the monsoon season? What values have you learnt from this report?
Answer:(a) Based on the pro-assessment given by the Meteorological Department of the Government of India that there may be deficient rainfall, the State Government should have taken advance action to preserve more water in the reservoirs so that fish breeding is not dependent on the rainfall. They could have reduced other water consuming activities to take care of this problem in advance They can also stop issuing licenses to individual persons for fishing in the streams, who are only interested in fishing as a hobby. (b) From this passage I have learnt that, Government is taking major steps in creating awareness among fishermen. It also shows that the weather forecast creates awareness about coming events and some adjustments can be made.
160) A recent newspaper report highlighted the following information Expressing inability to spare more water. Chief Minister of Karnataka said the state was not in a position to meet Tamil Nadu's demand, as a severe drought, a weak (South-West) monsoon and deficit rainfall in the catchment areas of the river basin have led to drastic fall in the rain-fed reservoirs. We need to look at our requirement before sharing water with Tamil Nadu. As we need water for our farmers, we can not give more to Tamil Nadu; he said. Read the above passage and answer the following questions The above report shows India's dependence on the monsoon. Do you think the Chief Minister was correct in not releasing water for Tamil Nadu What should the states do in the long-term to be less dependent on a good monsoon and thus prevent disputes? (b)What values have you learnt from this newspaper report?
Answer: (a) The Chief Minister was correct in his decision, because he is primarily responsible to the people in his state, as they have elected him. However what should have been done by him and the Chief Minister of Tamil Nadu is to chalk out an action plan on how to divide the river waters in case the monsoon fails, as has happened now. If such an agreement had been made before the start of the monsoon, no chance dispute would have arisen. (b) From this newspaper report I have learnt that proper planning and management is needed to deal with natural calamities.