NCERT Solutions for Class 9 Geography Chapter 4 – Climate (Social Science), contains solutions to various questions in Exercise for Chapter 4. At the end of the Solutions, all the keywords which are important to understand Climate Class 9 Geography, have been explained in a simple and easy to understand manner. We are providing NCERT Solutions for Class 9 all subjects which can be accessed by clicking here.
NCERT Solutions for Class 9 Geography Chapter 4 – Climate Exercises includes Question/Answers which helps you to understand the topic covered in Climate Class 9 Geography (Social Science), in a better manner to help you to score good marks in your examinations.
NCERT Solutions for Class 9 Geography Chapter 4 – Climate – NCERT Exercises
Ques.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?
(ii) The wind blowing in the northern plains in summers is known as:
(a) Kaal Baisakhi
(c) Trade Winds
(d) None of the above
(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
(iv) Monsoon arrives in India approximately in:
(a) Early May
(b) Early July
(c) Early June
(d) Early August
(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
Ans.1: Correct alternatives:
(i) (b) Mawsynram
(ii) (b) Loo
(iii) (a) Cyclonic depression
(iv) (c) Early June
(v) (c) Cool nights and cold days
Ques.2: Answer the following questions briefly.
(i) What are the controls affecting the climate of India?
(ii) Why does India have a monsoon type of climate?
(iii) Which part of India does experience the highest diurnal range of temperature and why?
(iv) Which winds account for rainfall along the Malabar Coast?
(v) What are Jet streams and how do they affect the climate of India?
(vi) Define monsoons. What do you understand by “break” in monsoon?
(vii) Why is the monsoon considered a unifying bond?
(i) The controls affecting the climate of India are:
- Distance from the sea
- Relief features
- Pressure and winds
- Pressure and surface winds
- Upper air circulation
- Western cyclonic disturbances and tropical cyclones.
(ii) India has a monsoon type of climate due to the following reasons:
- Differential heating and cooling of land and water
- A shift in the position of ITCZ
- Development of high-pressure area in the east of Madagascar
- Intense heating of the Tibetan plateau
- El Nino phenomena
- The movement of westerly jet streams
(iii) The northwestern part of India experiences the highest diurnal range of temperature. As this region is covered by the Thar Desert, the land heats up quickly in the day time, and there is no presence of any major water body to moderate the temperature. As the land cools down quickly at night, the temperature drops quickly.
(iv) The southwest monsoon winds account for rainfall along the Malabar Coast.
(v) Jet streams are a narrow belt of fast-flowing winds in the upper reaches of the troposphere. These winds blow in the westerly direction, over a height of 12,000 meters. Their speed varies from 110 km/h in summers to 184 km/h in winters. They have a major impact on the climate of India as the westerly flow of these winds south of Himalayas creates a depression in the Indian subcontinent, attracting the western cyclonic disturbances.
(vi) The seasonal reversal of wind direction is known as the monsoon. The word monsoon is derived from the Arabic word ‘mausim’ meaning season. The breaks in monsoon refer to the wet and dry spells during the monsoon season. These breaks are a result of the movement of the monsoon troughs. The northward or southward movement of the monsoon trough determines the breaks in the monsoons. The rainfall is widespread in the regions where the trough is present.
(vii) The monsoon is considered as a unifying bond due to the following reasons:
- This seasonal reversal of winds provides a rhythmic pattern to the seasons.
- The Indian landscape, agriculture and flora and fauna are all centred around the monsoons.
- Major festivals are celebrated at the onset of monsoons.
- The monsoon rains are a source of water for the entire humankind.
- All the major and minor river valley units are also united by the monsoons.
Ques.3: Why does the rainfall decrease from the east to the west in Northern India?
Ans.3: The rainfall decreases from the east to the west in Northern India as the rain-bearing winds eventually lose moisture when moving from the east to the west.
Ques.4: Give reasons as to why
(i) Seasonal reversal of wind direction takes place over the Indian subcontinent?
(ii) The bulk of rainfall in India is concentrated over a few months.
(iii) The Tamil Nadu coast receives winter rainfall.
(iv) The delta region of the eastern coast is frequently struck by cyclones.
(v) Parts of Rajasthan, Gujarat and the leeward side of the Western Ghats are drought-prone.
(i) The seasonal reversal of wind direction takes place over the Indian subcontinent as there is a rise of pressure difference whereby a low-pressure trough is formed. The process of El Nino also aids this seasonal reversal of winds.
(ii) The monsoon reaches the southern peak of India by in the first week of June and by mid-July, it completes the advancement process and covers the entire country. By September, the monsoon begins to withdraw from the subcontinent. Hence, the bulk of rainfall in India is concentrated from July to August.
(iii) As Tamil Nadu lies on the leeward side of the mountains, it does not receive rainfall form from the southwest monsoons. When the monsoon retreats due to the development of low pressure over the Bay of Bengal, Tamil Nadu receives rainfall from the northeast monsoons.
(iv) As the Bay of Bengal experiences frequent pressure changes, the delta region of the eastern coast is frequently struck by cyclones.
(v) Parts of Rajasthan, Gujarat and the leeward side of the Western Ghats are drought-prone as they lie in the rain-shadow regions. Rajasthan and Gujarat lie on the rain-shadow area of the Aravalli mountain ranges.
Ques.5: Describe the regional variations in the climatic conditions of India with the help of suitable examples.
Ans.5: There are major climatic variations in the climatic conditions of India.
- A major variation exists in the temperature and precipitation at different places. The temperature in Rajasthan may go as high as 50⁰C while around the same time It could be near 20⁰C in Jammu and Kashmir.
- The night time temperatures also show major differences. The night time temperature in Thiruvananthapuram can be 22⁰C. however, during the same time, the temperature in Drass in Jammu and Kashmir could be as low as -45⁰C.
- The temperature also shows variations in the same season as well. During winters, the temperatures in north India remain low but maybe average and moderate in south India as the temperature increases from north to south.
- During summers, mercury may touch as high as 50⁰C in Rajasthan but be as low as 20⁰C in Jammu and Kashmir.
Ques.6: Discuss the mechanism of monsoons.
Ans.6: The seasonal reversal of wind direction is known as the monsoon. This wind reversal of winds is responsible for rains in the Indian subcontinent. The mechanism of monsoon is aided by the following mechanisms.
- The differential heating and cooling of land and water results in a low-pressure region over the Indian landmass which attracts winds from the high-pressure regions.
- The Inter-Tropical Convergence Zone (ITCZ) shifts over the Ganga plain in summers. This creates a monsoon trough over the region.
- There is a high-pressure area east of Madagascar, at nearly 20⁰S over the Indian Ocean.
- The intense heating of the Tibetan plateau during summers creates low pressure, which sets in the strong vertical air currents.
- The westerly jet stream to the north of Himalayas and tropical easterly jet stream over the Indian Peninsula also aid the monsoons in India.
- The reversal of winds over the Pacific Ocean results in the Southern Oscillations. This also affects the Indian monsoon.
- The Indian monsoons are also affected by the replacement of the cold Peruvian current by the hot currents. This phenomenon is known as El Nino.
Ques.7: Give an account of weather conditions and characteristics of the cold season.
Ans.7: The weather conditions during and the characteristics of the cold season are as follows:
- The cold weather season begins in mid-November and stays till February in northern India.
- The coldest months are December and January.
- The temperature increases from north to south. The temperature in south India ranges between 24⁰-25⁰C while in north India, it ranges between 10⁰-15⁰C.
- Days are warm and nights are cold. Frost is a common sight in north India. Even higher altitudes like Himalayas experience snowfall.
- The winters are dry as the winds blow from land to the sea. These are northeast trade winds. These winds cause a small amount of rainfall in Tamil Nadu.
- During the cold-weather season, there is an inflow of the western cyclonic disturbances from the west. These originate over the Mediterranean Sea. They cause winter rainfall over plains and snow over mountains.
- Peninsular India does not have a well-defined winter season due to the moderating influence of the sea.
Ques.8: Give the characteristics and effects of the monsoon rainfall in India.
Ans.8: The characteristics of the monsoon rainfall in India are:
- The monsoons begin in India around early June and last up to mid-September, for 100-120 days.
- The normal rainfall increases around the time of the arrival of the monsoons. This is known as the burst of the monsoon.
- The monsoons reach the Indian landmass around the first week of June.
- The rainfall is unevenly distributed over the country.
The effects of the monsoon rainfall over India is as follows:
- The agricultural activities in India are majorly rain-fed. Thus, good monsoons imply good harvest, and bad monsoons imply low harvests.
- As the rainfall is distributed unevenly across the country, some areas are drought-stricken and the others are prone to heavy floods.
- The monsoons are a unifying bond of the nation as they unite people across various cultures and regions and bind them together.
Important Terms Relevant for NCERT Solutions for Class 9 Geography Chapter 4 – Climate
Climate: The total of weather conditions of a large area over a long time, mostly 31 years, is known as climate.
Weather: Weather refers to the atmospheric conditions of any area at a point of time.
Monsoon: The seasonal reversal of winds is known as monsoon.
Coriolis force: The force generated by the rotation of the earth is the Coriolis Force.