PadhaiKendra, an esteemed educational platform, has crafted NCERT Solutions for Class 9 Social Science Geography Chapter 4 Climate, meticulously curated by subject matter experts. These solutions are specifically designed to aid students in their CBSE exam readiness. Prior to this chapter, students have delved into landforms (Chapter 2) and the drainage system of India (Chapter 3), forming the foundation of their knowledge. Chapter 4 delves into the crucial third element: Climate.
Within this chapter, students will explore India’s climate, the factors influencing it, the Indian monsoon, its onset and withdrawal, the distinctive seasons in India, and the pattern of rainfall distribution. The exercise section presents questions encompassing these topics. To facilitate preparation for the CBSE exams, we have compiled the answers to these exercise questions in the form of NCERT Solutions Class 9 Geography Chapter 4 Climate PDF. To access this resource, students can download the PDF via the provided link and utilize it as a reference tool during their exam preparations.
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
(c) Cherrapunji
(b) Mawsynram
(d) Guwahati
Ans. Mawsynram
(ii) The wind blowing in the northern plains in summer is known as:
(a) Kaal Baisakhi
(c) Trade Winds
(b) Loo
(d) None of the above
Ans. Loo
(iii) Monsoon arrives in India approximately in:
(a) Early May
(c) Early June
(b) Early July
(d) Early August
Ans. Early June
(iv) 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. Warm days and cold nights
2. Answer the following questions briefly.
(i) What are the controls (factors) affecting the climate of India?
Ans. The climate of India is influenced by several factors, including the following controls:
Latitude: India is located in tropical and subtropical latitudes, which contribute to its overall warm climate.
The Tropic of Cancer passes through the middle of the country, leading to the presence of a diverse range of climatic zones.
Altitude: The variation in altitude across different regions of India significantly affects its climate.
Higher altitude areas, such as the Himalayas, experience cooler temperatures while lower-lying coastal regions have warmer climates.
Distance from the Sea: Proximity to the sea plays a crucial role in shaping India’s climate.
Coastal areas benefit from the moderating influence of the sea, resulting in milder temperatures and higher humidity. Inland regions, far from the sea, experience more extreme temperature variations.
Pressure and Winds: The movement of air masses, influenced by pressure systems, impacts India’s climate.
The southwest and northeast monsoons, driven by seasonal pressure changes, bring significant rainfall to different parts of the country during specific periods.
Ocean Currents: Ocean currents, particularly the warm and cold currents in the Indian Ocean, influence the moisture content and temperature of coastal regions.
They can either enhance or reduce the rainfall in specific coastal areas.
Topography and Relief Features: The varied topography of India, including mountains, plains, plateaus, and coastal areas, influences the distribution of rainfall, temperature, and wind patterns.
Mountains act as barriers to the movement of air masses and play a crucial role in determining the distribution of rainfall across different regions.
Vegetation and Forests: The presence of forests and vegetation cover affects local climate conditions.
Forests help in retaining moisture, regulating temperature, and influencing rainfall patterns through mechanisms such as transpiration and evapotranspiration.
These controls collectively contribute to the diverse climate patterns observed across India, including variations in temperature, precipitation, and seasonality.
(ii) Why does India have a monsoon type of climate?
Ans. India’s climate is often referred to as the “monsoon” type, which signifies the seasonal reversal of wind direction throughout the year. This distinctive climate pattern is characterized by significant seasonal changes in weather conditions, particularly noticeable in the interior regions of the country. Coastal areas, on the other hand, exhibit less temperature variation but experience variations in the pattern of rainfall.
India can be divided into four main seasons, although regional variations exist. These seasons are the cold weather season, the hot weather season, the advancing monsoon, and the retreating monsoon.
The monsoon winds exert a strong influence on India’s climate. The monsoon season typically lasts for approximately 100-120 days, spanning from early June to mid-September. This period is crucial as it brings the majority of India’s annual rainfall and plays a vital role in agricultural practices and water resources management.
(iii) Which part of India does experience the highest diurnal range of temperature and why?
Ans. The interior regions of India, specifically the northwestern parts, experience the highest diurnal range of temperature. This is primarily due to the absence of moderating influences from large water bodies such as oceans or seas. As a result, these inland areas undergo significant temperature fluctuations between day and night, leading to a high diurnal range of temperature.
(iv) Which winds account for rainfall along the Malabar coast?
Ans. Winds responsible for rainfall along the Malabar Coast are Southwest monsoon winds.
(v) Define monsoons. What do you understand by “break” in monsoon?
Ans. Monsoons refer to the seasonal wind patterns characterized by the reversal of wind direction during a specific time of the year. These winds bring about significant changes in weather conditions, particularly in terms of rainfall, across large geographic regions.
The term “break” in the context of monsoons refers to a temporary interruption or weakening of the monsoon rainfall. It is a phase during the monsoon season when there is a lull or reduction in rainfall activity for a few days or weeks. This break period is characterized by a temporary shift or weakening of the prevailing wind patterns, resulting in reduced or sporadic rainfall during that time. The break in monsoon rainfall is a natural occurrence and is part of the overall seasonal variability associated with the monsoon climate.
(vi) Why is the monsoon considered a unifying bond?
Ans. The monsoon holds a remarkable unifying influence over the Indian subcontinent, evident in the rhythmic cycle of seasons brought about by the seasonal shift in wind systems and associated weather conditions. The monsoons are characterized by the expected uncertainties of rainfall and its uneven distribution. This climatic phenomenon profoundly impacts the Indian landscape, including its flora, fauna, agricultural practices, and the lives of its people, who eagerly anticipate its arrival year after year. From north to south and from east to west, the monsoon winds bind the entire country together, providing the vital water needed to initiate agricultural activities. In this process, the river valleys that carry this water serve as a cohesive force, uniting as a single river valley unit.
3. Why does the rainfall decrease from the east to the west in Northern India?
Ans. The decrease in rainfall from east to west in Northern India can be attributed to the presence of the Aravalli Range and the Thar Desert. The Aravalli Range acts as a barrier, blocking the moisture-laden winds coming from the Bay of Bengal, leading to reduced rainfall in western regions. Additionally, the Thar Desert, located in the western part of Northern India, creates a rain shadow effect, further reducing the amount of rainfall in the western areas.
In short, it can be said that the winds lose the contained moisture while moving from east to west in Northern India.
4. Give reasons as to why.
(i) Seasonal reversal of wind direction takes place over the Indian subcontinent?
Ans. The seasonal reversal of wind direction over the Indian subcontinent occurs due to the following reasons:
Differential Heating: Differential heating of land and water surfaces during different seasons creates variations in air pressure.
This pressure difference leads to the formation of low-pressure areas over the Indian subcontinent during certain seasons, causing winds to blow from high-pressure areas towards low-pressure areas.
The shift in Inter-Tropical Convergence Zone (ITCZ): The movement of the Inter-Tropical Convergence Zone, which is the region where trade winds from the northern and southern hemispheres converge, plays a crucial role in the seasonal reversal of wind direction.
During certain seasons, the ITCZ shifts northward, bringing with it moisture-laden winds toward the Indian subcontinent.
Influence of Ocean Currents: Ocean currents, such as the El Niño-Southern Oscillation (ENSO) phenomenon, can have a significant impact on the wind patterns over the Indian subcontinent.
El Niño, characterized by the warming of the central and eastern tropical Pacific Ocean, can disrupt the normal wind patterns and influence the seasonal reversal of winds in the region.
Topographical Features: The presence of topographical features, such as the Himalayas and the Tibetan Plateau, can affect wind patterns and contribute to seasonal reversal.
These features act as barriers, forcing the winds to ascend, cool, and condense moisture, resulting in significant rainfall on the windward side.
The combination of pressure differences, shifts in the Inter-Tropical Convergence Zone, the influence of ocean currents like El Niño, and the impact of topographical features contribute to the seasonal reversal of wind direction over the Indian subcontinent.
(ii) The bulk of rainfall in India is concentrated over a few months.
Ans. The majority of rainfall in India is concentrated over a few months, typically during the monsoon season. The monsoon season in India generally lasts from June to September. During this period, the South West Monsoon winds bring heavy rainfall to various parts of the country.
The concentration of rainfall over a few months is a characteristic feature of the monsoon climate in India. The monsoon rains account for a significant portion of the annual precipitation, and the intensity of rainfall during this period is often high. These concentrated monsoon rains play a crucial role in replenishing water sources, supporting agricultural activities, and maintaining the overall ecological balance.
(iii) The Tamil Nadu coast receives winter rainfall.
Ans. The Tamil Nadu coast receives winter rainfall because of North-East monsoon winds.
(iv) The delta region of the eastern coast is frequently struck by cyclones.
Ans. The Bay of Bengal faces frequent pressure changes due to which 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.
Ans. Parts of Rajasthan, Gujarat, and the leeward side of the Western Ghats are drought-prone because they fall in the rain shadow region of the Aravali Mountains.
5. Describe the regional variations in the climatic conditions of India with the help of suitable examples.
Ans.
⇒ The cold weather season in northern India typically commences in mid-November and lasts until February. The coldest months are December and January, particularly in the northern part of the country. There is a gradual decrease in temperature from south to north.
For example, Chennai, located on the eastern coast, experiences average temperatures ranging between 24°-25° Celsius, while the northern plains witness temperatures between 10°C and 15° Celsius. Days are relatively warm, while nights are chilly. Frost is common in the north, and the higher slopes of the Himalayas receive snowfall.
⇒ Moving into March, the Deccan plateau records the highest temperature of around 38° Celsius. April sees temperatures of about 42° Celsius in Gujarat and Madhya Pradesh. May brings scorching temperatures of 45° Celsius in the northwestern parts of the country. However, peninsular India experiences lower temperatures due to the moderating influence of the nearby oceans.
6. Give an account of weather conditions and characteristics of the cold season.
Ans. The cold weather season in northern India begins in mid-November and extends until February. December and January are the coldest months in this region. As one moves from south to north, the temperature gradually decreases. For example, Chennai on the eastern coast experiences average temperatures between 24°-25° Celsius, while the northern plains have temperatures ranging from 10°C to 15° Celsius. During this season, the days are warm, and the nights are cold. Frost is common in the north, and the higher slopes of the Himalayas receive snowfall.
In terms of wind patterns, the northeast trade winds prevail over the country during the cold weather season. These winds blow from land to sea, resulting in dry conditions for most parts of the country. However, the Tamil Nadu coast receives some rainfall as the winds blow from the sea to land in this region. In the northern part of the country, a weak high-pressure region develops, with light winds moving outwards from this area. These winds, influenced by the topography, blow through the Ganga Valley from the west and northwest.
The weather during the cold weather season is characterized by clear skies, low temperatures, low humidity, and variable winds. One notable feature of this season in the northern plains is the arrival of cyclonic disturbances from the west and northwest. These low-pressure systems originate over the Mediterranean Sea and western Asia, moving into India along the westerly flow. They bring much-needed winter rains to the plains and snowfall in the mountains. Although the overall amount of winter rainfall, locally known as ‘Mahawat,’ is relatively small, it is of great significance for the cultivation of ‘rabi’ crops.
In contrast, the peninsular region of India does not have a well-defined cold season. The influence of the sea moderates the temperature patterns, resulting in minimal seasonal temperature changes during winter.
7. Give the characteristics and effects of the monsoon rainfall in India.
Ans. The Monsoon, unlike the trade winds, is characterized by its pulsating nature, influenced by various atmospheric conditions encountered over the warm tropical seas. It lasts for a duration of 100-120 days, spanning from early June to mid-September. During its arrival, there is a sudden increase in normal rainfall, which continues consistently for several days. This period is known as the ‘burst’ of the monsoon and can be distinguished from the pre-monsoon showers.
The monsoon typically begins at the southern tip of the Indian peninsula, usually around the first week of June. It then branches into two streams: the Arabian Sea branch and the Bay of Bengal branch. The Arabian Sea branch reaches Mumbai around ten days later, approximately on the 10th of June, showing a relatively rapid progression. Similarly, the Bay of Bengal branch advances swiftly and reaches Assam in the first week of June.
The presence of high mountains causes the monsoon winds to deflect westward over the Ganga Plains. By mid-June, the Arabian Sea branch of the monsoon arrives over Saurashtra-Kachchh and the central part of the country. The Arabian Sea and Bay of Bengal branches merge over the northwestern region of the Ganga Plains. Delhi generally receives the monsoon showers from the Bay of Bengal branch by the end of June (tentatively on the 29th of June). By the first week of July, western Uttar Pradesh, Punjab, Haryana, and eastern Rajasthan experience the monsoon. By mid-July, the monsoon reaches Himachal Pradesh and extends to the rest of the country.
Map Skills-
Question- On an outline map of India, show the following.
(i) Areas receiving rainfall over 400 cm.
(ii) Areas receiving less than 20 cm of rainfall.
(iii) The direction of the South-West Monsoon over India.
Answer:
