ClimateClass 11 India Physical Environment NCERT Solutions
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Solution 1 of 3
Q1EXERCISES
Choose the right answer from the four alternatives given below.
(i)
What causes rainfall on the coastal areas of Tamil Nadu in the beginning of winters?
(a)
South-West monsoon
(b)
Temperate cyclones
(c)
North-Eastern monsoon
(d)
Local air circulation
(ii)
What is the proportion of area of India which receives annual rainfall less than 75 cm ?
(a)
Half
(b)
One-third
(c)
Two-third
(d)
Three-fourth
(iii)
Which one of the following is not a fact regarding South India?
(a)
Diurnal range of temperature is less here.
(b)
Annual range of temperature is less here.
(c)
Temperatures here are high throughout the year.
(d)
Extreme climatic conditions are found here.
(iv)
Which one of the following phenomenon happens when the sun shines vertically over the Tropic of Capricorn in the southern hemisphere?
(a)
High pressure develops over North-western India due to low temperatures.
(b)
Low pressure develops over North-western India due to high temperatures.
(c)
No changes in temperature and pressure occur in north-western India.
(d)
'Loo' blows in the North-western India.
Solution
(i) (c) North-Eastern monsoon
During October and November, the northeast monsoon winds cross over the Bay of Bengal, pick up moisture, and cause significant rainfall over the Tamil Nadu coast, southern Andhra Pradesh, southeast Karnataka, and southeast Kerala.
(ii) (b) One-third
Based on the distribution of rainfall described, the areas of low rainfall (50-100 cm) and inadequate rainfall (below 50 cm) together constitute a large portion of the country. This includes Western Uttar Pradesh, Delhi, Haryana, Punjab, Jammu and Kashmir, eastern Rajasthan, Gujarat, the Deccan Plateau, Ladakh, and most of western Rajasthan. Cumulatively, this region, which receives less than 75 cm of annual rainfall, accounts for approximately one-third of India's total area.
(iii) (d) Extreme climatic conditions are found here.
South India, due to its peninsular location and proximity to the equator, experiences a moderating influence from the sea. This results in an equable climate with high temperatures throughout the year and a low annual and diurnal range of temperature. Extreme climatic conditions, characterized by very hot summers and very cold winters, are a feature of the interior parts of north India, not the south.
(iv) (a) High pressure develops over North-western India due to low temperatures.
When the sun shines vertically over the Tropic of Capricorn in the southern hemisphere (around December 22nd), it is winter in the northern hemisphere. This leads to low temperatures over the northern plains of India. Cold air is dense and sinks, creating a feeble high-pressure zone over northwestern India.
Q2EXERCISES
Answer the following questions in about 30 words.
(i)
What is the Inter-Tropical Convergene Zone?
(ii)
What is meant by 'bursting of monsoon'? Name the place of India which gets the highest rainfall.
(iii)
Which type(s) of cyclones cause rainfall in north-western India during winter? Where do they originate?
Solution
(i) What is the Inter-Tropical Convergence Zone?
The Inter-Tropical Convergence Zone (ITCZ) is a low-pressure zone located near the equator where the trade winds from the northern and southern hemispheres converge. This convergence forces the air to ascend, leading to cloud formation and precipitation. In summer, this zone shifts northwards over the Gangetic plain in India, forming the monsoon trough.
(ii) What is meant by 'bursting of monsoon'? Name the place of India which gets the highest rainfall.
The 'bursting of the monsoon' refers to the sudden onset of the moisture-laden southwest monsoon winds, which is often associated with violent thunder and lightning. This abrupt arrival of rain causes a substantial drop in temperature. The place in India that receives the highest rainfall is Mawsynram, located in the Khasi Hills of Meghalaya.
(iii) Which type(s) of cyclones cause rainfall in north-western India during winter? Where do they originate?
Weak temperate cyclones cause rainfall in north-western India during winter. These cyclones originate over the east Mediterranean Sea. They travel eastwards across West Asia, Iran, Afghanistan, and Pakistan before reaching the northwestern parts of India, bringing beneficial rain for rabi crops.
Q3EXERCISES
Answer the following questions in not more than 125 words.
(i)
Notwithstanding the broad climatic unity, the climate of India has many regional variations. Elaborate this statement giving suitable examples.
(ii)
How many distinct seasons are found in India as per the Indian Meteorological Department? Discuss the weather conditions associated with any one season in detail.
Solution
(i) Notwithstanding the broad climatic unity, the climate of India has many regional variations. Elaborate this statement giving suitable examples.
India's climate is broadly unified by the monsoon regime, characterized by the seasonal reversal of winds. This monsoonal rhythm provides a common climatic framework for the entire subcontinent. However, within this broad unity, there are significant regional variations that create diverse climatic sub-types.
These variations are evident in temperature and rainfall patterns:
- Temperature: There is a vast difference in temperature across regions and seasons. For instance, in summer, the temperature in western Rajasthan can touch 55°C, while in Tawang (Arunachal Pradesh) it may be only 19°C. In winter, Drass (Ladakh) can experience temperatures as low as minus 45°C, while Thiruvananthapuram on the same night might record 22°C.
- Rainfall: The amount and type of precipitation also vary greatly. The Himalayas receive snowfall, while the rest of the country gets rain. Mawsynram in Meghalaya receives over 1,080 cm of annual rainfall, whereas Jaisalmer in Rajasthan gets less than 9 cm. Similarly, during the southwest monsoon, the Coromandel coast remains dry while the west coast receives heavy rainfall.
These examples clearly show that despite the overarching monsoonal character, India's climate is marked by significant regional diversity.
(ii) How many distinct seasons are found in India as per the Indian Meteorological Department? Discuss the weather conditions associated with any one season in detail.
As per the Indian Meteorological Department, India has four distinct seasons:
- The Cold Weather Season (Winter)
- The Hot Weather Season (Summer)
- The Southwest Monsoon Season (Rainy Season)
- The Retreating Monsoon Season (Autumn)
Weather Conditions in the Cold Weather Season (Winter):
This season typically begins in mid-November and lasts till February, with December and January being the coldest months in northern India.
- Temperature: In north India, the mean daily temperature stays below 21°C, and night temperatures can drop below freezing in Punjab and Rajasthan. The cold is intensified by the continental location, cold waves from snowfall in the Himalayas, and cold winds from the Caspian Sea. In contrast, peninsular India does not have a well-defined cold season due to the moderating influence of the sea, with temperatures remaining high.
- Pressure and Winds: A feeble high-pressure area develops over the northern plains, causing light winds to blow outwards from the northwest towards the low-pressure area over the Indian Ocean. These are the dry Northeast Monsoon winds.
- Rainfall: Most of India remains dry. However, weak temperate cyclones from the Mediterranean Sea cause light rainfall in northwestern India (Punjab, Haryana), which is crucial for rabi crops. The northeast monsoon, after picking up moisture from the Bay of Bengal, causes torrential rain on the Tamil Nadu coast.