Climate Class 9 Notes Geography Chapter 4 - PDF Download
In Class 9 Geography Chapter 4 Climate revision notes, we come to learn that the word ‘Climate’ is derived from the word “Klima” which means ‘inclination’ in Greek. Over the years, ‘Klima’ evolved into ‘clime’ which later went on to mean the atmospheric condition of a region. Climate indicates the average weather condition of a particular place for 30 years or more. The factors that characterise the climate of a place are temperature, air pressure, wind, humidity, precipitation, etc. of a place throughout the year. Download the notes on Vedantu to know more about the chapter.
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Climate is the sum total of weather situations and variations over a large area for a long period of time, normally more than 30 years.
Weather may be described as the state of the atmosphere measured at a specific time.
Components of climate and weather are identical i.e. humidity, precipitation, atmospheric stress, wind and temperature.
Our earth is split into many climatic zones. India is stated to have the monsoon kind of weather. There is a well known pattern of climate in the country however there are visible variations that exist regionally. The most crucial aspects of the climate are temperature and precipitation.
Factors Affecting India's Climate
i. Latitude: From the Rann of Kutch withinside the west to Mizoram in the east passes the Tropic of Cancer, dividing the country into parts. To the south lies the tropical region and to the north lies the subtropical area.
ii. Altitude: To the north stands the Himalayan range with a peak of approximately 6000 metres. In the south, there are huge coastal stretches with maximum elevation as much as 30 metres. The Himalayas prevent the cold chilly winds from Central Asia from coming into the country.
iii. Wind and Pressure: The pressure and wind system affecting the weather and climate situations in India are ruled through certain parameters. These are pressure and surface winds, western cyclones and tropical cyclones and the top air stream. India is located in the region of the northeasterly winds that begins from the subtropical high-pressure belts of the northern hemisphere and blow towards the south. These winds get deflected because of the Coriolis effect and circulate toward the equatorial low- stress belt. These winds do not have moisture; for this reason, carry very little rain at all.
During winters, a high-pressure region prevails north of the Himalayas. During summers, there may be an entire reversal of wind direction. As low pressure develops over the landmass causing the wind to blow from oceans to landmass, it collects moisture from the Indian ocean and blows withinside the south-east direction. Upon crossing the equator, the wind turns right in the direction of the region wherein low pressure is created over the Indian subcontinent. This is referred to as the southwest monsoon wind which brings in massive rainfall over the landmass of India. Upper flow referred to as the jet streams are controlled through westerly winds.
Indian Monsoons: Arrival and Retreat
Indian monsoons have a period of one hundred to two hundred days that is from the early of June to the mid of September. On the appearance of monsoons, the regular rainfall will increase suddenly and this heavy rainfall lasts for several days. This phenomenon is referred to as the burst of the monsoons. This climate situation is distinguishable from the pre-monsoon showers. The monsoon approaches the southern tip of the Indian peninsula during the first week of June from which it is divided into two branches one the Arabian Sea branch and the other one Bay of Bengal branch. The Arabian Sea branch reaches Mumbai ten days later whereas the Bay of Bengal branch during the first week of June.
Mountains are liable for the monsoon winds to deflect West in the direction of the Ganga plains, The Arabian Sea branch through the middle of June seems over Saurashtra and Kutch and central India. The branches of southwesterly monsoons meet at the Ganga plains. Delhi gets showers from the Bay of Bengal branch through the end of June, and Punjab, Haryana, Eastern Rajasthan and Western UP enjoy showers through the first week of July. By mid-July, the monsoon winds cover the entire country.
The low pressure created over the northern Gangetic plains intensifies and draws trade winds from the southern hemisphere. These winds originate over the regions of warm subtropical Southern Ocean and pass the equator to blow in a southeasterly path to go into India. The winds are moisture-laden. The windward aspect of the Western ghats is hit by these winds and experiences heavy rainfall of more than 250cm. The rain shadow regions of Madhya Pradesh in the Deccan plateau additionally acquire a little rain. The north-eastern part of the country gets the most rainfall for the duration of this period. Mawsynram, found in the Khasi hills, gets the highest average rainfall in the world. In the Ganga valley, it decreases from east to west which is from Rajasthan and Gujarat receiving scanty rainfall.
Retreating Monsoon or the Transition Season:
Between October and November the apparent movement of the sun is closer to the south. The monsoon trough will become weaker and is replaced by high-pressure systems. Southwest monsoon initiated retreating from the country by the start of October. It withdraws from the northern parts of the country first. Retreating monsoon is related to clean skies and rise in the temperature. By early November the low-pressure situations get shifted over the Bay of Bengal which creates a cyclonic disturbance that generally originates over the Andaman sea. The cyclone hits the eastern coast of India inflicting massive damage.
Monsoons as a Unifying Bond
Monsoons are a unifying bond withinside the country.Though the monsoons are marked by seasonal and local variations, the entire country is keen for its arrival. Agriculture is completely dependent on the monsoons. India being an agriculture centric country, rainfall and monsoons are necessary for the country.
Definition of Weather in Climate Chapter Class 9 Notes
The term weather denotes the atmospheric condition of a particular place for one day or a few hours. It depends upon temperature, humidity, wind speed, etc.
Difference Between Climate and Weather in Climate Chapter Class 9 Notes
In Climate Geography Class 9, you will learn about climate and weather, and how they are different from each other. Though the components and variables of both climate and weather are the same, still there is a difference between the two.
Weather conditions of a place deal with the day-to-day variations of its atmospheric condition. On the other hand, the climate of a place is the average of the weather conditions for 30 years or more. Weather is frequently changeable but the climate is a standard concept for a given period of time.
Factors that Control the Climate of a Place
As discussed in the Climate Chapter Class 9 Notes, the following factors affect the climate of a geographical region:
Latitude: The places which are located near the equator receive direct rays of the sun throughout the year. So, the temperature remains high almost throughout the year. On the other hand, the places which are located near the poles receive slanting sun rays and thus have low temperature throughout the year.
Altitude: The temperature decreases by 6 degrees every 1km from the sea level; this is known as the normal lapse rate.
Distance From the Sea: The places which are located near the sea have a moderate climate, but regions which are located far away from the sea have an extreme type of climate. This happens because two types of wind always prevail near the coast i.e., land breeze and sea breeze.
Relief Features: The presence of some significant relief features also plays a role in shaping the climate of a place.
Humidity: The humidity of a place is highly affected by its distance from the sea.
Ocean Currents: If cold ocean currents are circulating near the shores of a country, then the country will have a cooler climatic condition than the country where warm ocean currents are active near the shores.
Factors Affecting India’s Climate
The factors which control the diversified climatic conditions of India are as follows:
Latitude - Places located in the northern part of India have a cold climate while places in the southern states have warm climatic conditions.
Altitude - Places located on the slopes of the Himalayas or other hill ranges have colder climates than the places on the plains.
Presence of Winds - In the north-west part of India, local winds prevail during summer months which control the climatic conditions of that region to a huge extent.
Relief - The relief features of a place, that is, whether it is on the plainland or located on the hills or plateaus determine the climatic conditions of a place.
You will learn about these factors in detail in Class 9 Geography Chapter 4 Climate notes.
Indian Monsoon in Climate Notes
Monsoon wind is a seasonal wind which mainly prevails in the south and south-east Asia. The Arabic word “mausim” meaning season is the origin of the term “monsoon.” During the months of May-September, it blows from south-west direction to the northeast direction and brings heavy rainfall in the Indian subcontinent. Again, during the Reverse Monsoon period, this wind blows from northeast to south-west.
Formation of Monsoon in Climate Class 9 Notes
Monsoon winds are generated due to the difference in the heating and cooling rates of land and sea. During the summer season, a high-pressure cell forms in the east of Madagascar and a low-pressure cell in the Tibetan plateau. Due to the presence of these two pressure cells, monsoon winds develop and enter India in two branches- the Bay of Bengal branch and the Arabian sea branch causing heavy rainfall. At the end of May, the monsoon hits the coast of Kerala and brings heavy rainfall in this region. It is also known as the Burst of Monsoon. All this is beautifully explained in the Class 9 Geography Chapter 4 Climate notes.
Seasons of India
The notes on Climate Geography Class 9 clearly speaks about the four seasons that are prevalent in India - summer, rainy, post-monsoon or transition period and the winter. During summer, in north-west India, a local hot wind prevails which is known as loo. Then, monsoon wind brings rains in the rainy season. After that, in the transition period, a mild climate prevails all over India. During winter, snowfall occurs in the northernmost and some northeastern parts of India.
To learn more about climate, download Climate Class 9 notes PDF download.
Did You Know?
How extreme India’s climate is!
Mawsynram in Meghalaya receives, on an average, 10,000 millilitres of rainfall in a year.
Rajasthan’s Churu is the hottest place in India. The temperature here reaches 50-degree Celsius during summer!
FAQs on Climate Class 9 Notes CBSE Geography Chapter 4 [Free PDF Download]
1. Write a Short Note on the Distribution of Rainfall in India.
In the Climate notes, the distribution of rainfall in India is discussed vividly. The western coast of India and northeastern parts receive the maximum amount of rainfall, while the places in states like Rajasthan and Gujarat receive very less rainfall.
Based on climate, rainfall and soil condition, the vegetation changes. In India, the distribution of rainfall is quite uneven and uncertain too; so it also affects the agriculture period of the country to some extent.
2. What is the Time Period for Retreating Monsoon?
From early November till December, the phase of retreating monsoon continues. During this time, the south-west monsoon winds return from the Indian subcontinent as the northeast monsoon winds. Then, it blows as a dry land breeze, but while crossing the Bay of Bengal, it collects moistures and causes heavy rainfall in Tamil Nadu, along with Kerala, Karnataka, etc. With the retreating of Monsoon, rainfall started to decrease but during this time period, several cyclones are formed in the Bay of Bengal which causes heavy rainfall in the coastal regions.
3. What do you mean by Breaks in Monsoons?
Monsoons refer to the seasonal wind direction during a year. During this time, Monsoons can have breaks in between. This means that there are dry and wet spells during the Monsoon season. These spells take place during the Monsoon rains only for a couple of days for a limited period of time. After which, the rains start to go on like usual. This process is known as 'breaks' in monsoons. This can occur at any place, at any time of the season.
4. Why is the Delta region of the eastern coast frequently struck by cyclones?
In November, the low-pressure conditions in the northwest of India are transferred to the Bay of Bengal. This transfer is related to the cyclonic depressions that take place at the Andaman Sea. These cyclones sometimes pass over the Indian eastern coast which causes widespread heavy rains. The cyclones in this region are tropical and destructive. The Delta regions of Godavari, Kaveri, and Krishna are often struck by these cyclones which in turn create a large amount of damage to property and life.
5. What are the major controls affecting the climate of India?
The Climate in India keeps changing according to the seasons. Each season has a different climatic condition. Climatic controls refer to the components which help in the regulation of temperature in a particular country or region. There are a total of six major controls that influence the effects of Climate in India. These controls include relief features, Ocean currents, distance from the sea, wind and pressure system, altitude, and latitude. These six climatic controls not only affect the climatic condition of India but it also affects the climate at any place.
6. What are the elements of weather and climate class 9 NCERT?
The weather conditions of an area are completely dependent on the climate of the area. The elements of weather and climate include precipitation, humidity, wind, atmospheric pressure, and temperature. Weather and Climate are two separate terms that can be defined individually. Weather refers to the atmospheric state at any given point of space and time. Climate is known to be the sum of weather conditions and variations that take place for a long period of time over a large area.
7. How can I top in Class 9 Geography?
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