CBSE Class 9 Social Science Geography Revision Notes Chapter 4

CBSE Class 9 Geography Chapter 4 Notes – Climate

Class 9 chapter 4 Geography notes: You shall come to learn about climate. The word is derived from the Greek word k’lima’ meaning inclination. Climate indicates the average weather condition of the country of a particular place for more than 30 years. The factors which characterise the climate are temperature, wind, air pressure, precipitation, humidity, and many more. You must go through these CBSE revision notes of Class 9 Geography Chapter 4 Notes for last-minute preparation.

CBSE Class 9 Geography Revision Notes 2023-24

Get Access to CBSE Class 9 Geoghraphy Revision Notes for all chapters for the academic year 2023-24

Chapter 4 Geography Class 9 Notes also tell you about the following:

• Climate is the total of weather variations and situations over a significant period, approximately 30 years, in a particular place.
• You can describe the weather as a state of the atmosphere measured at a specific time.
• Add another point about the differences between weather and climate.
• The components of weather and Climate are identical: atmospheric stress, humidity, precipitation, temperature, and wind.
• Our Earth is divided into different climatic conditions. India is considered to have a tropical climate. The north has humid tropical weather, the western coasts experience wet tropical weather, while the interior is a mixture of wet and dry tropical weather.

Extramarks also provides CBSE previous year question papers and important questions for better preparation for the students.

Class 9 geography chapter 4 climate notes

Factors Affecting India’s Climate

• Latitude – from Rann of Kutch in the west to Mizoram in the east, the tropic of Cancer passes, dividing the country into two halves. The tropical region lies in the north, and the subtropical region lies in the south.
• Altitude – the Himalayan range stands in the north at an average of 6,000 meters in height. In the south, the coastal area stretches to 30 meters. The Himalayan range stops Central Asia’s chilly air from entering India.
• Wind and pressure – the pressure and wind systems affect climatic situations. India is a region with northeasterly winds from subtropical high-pressure belts of the northern hemisphere. Such winds get deflected because of the Coriolis effect and circulate towards the low-stress belts.

The Class 9 chapter 4 Geography notes of NCERT books tell you about the concepts of climate and weather. During the winter season, a high-pressure region prevails in the Himalayan range. During the summer season, the wind direction stays in reversal mode. Low pressure develops on the landmass, which causes the wind to flow from oceans towards the landmass. Further, it collects moisture from the Indian Ocean and blows in the southeast direction.

Indian Monsoons: Arrival and Retreat:

The Indian monsoons have a period of a hundred to a hundred days, starting from June and ending around mid-September. The regular rainfall increases and the heavy rainfall persists for a few days. This is also known as the burst of monsoon.

In the first week of June, the monsoon winds reach the southern tip of the Indian peninsula and get divided into two branches, the Arabian Sea and the Bay of Bengal. The mountains make the monsoon winds deflect in the western direction. Delhi gains showers from the Bay of Bengal by the end of June. You can also go through CBSE sample papers and CBSE extra questions from Class 9 Geography notes chapter 4 and other subjects available on Extramarks website.

Monsoon:

The low pressure on the Gangetic plains draws trade winds from the southern hemisphere. These winds rise from the subtropical Southern regions. The windward aspect of the western ghats experiences heavy rainfall of more than 250 cm. The rainshadow regions of Madhya Pradesh in the Deccan Plateau require little additional rainfall. what is rainshadow? Why does it require ‘little’ additional rainfall? Avoid using vague comparative terms. Explain the windward aspect first. Insert note about the area known for the highest rainfall in India.

Most northeastern parts of the country experience rainfall during this period. In the Gangetic plains, it declines from east to west, from Rajasthan to Gujarat. The CBSE syllabus includes not only class 9 geo ch 4 notes but also includes mathematical formulas and other standard concepts.

Retreating Monsoon or the Transition Season:

Between October and November, the sun moves closer to the south. As a result, the monsoon trough (what is a monsoon trough?) becomes weaker and is replaced by high-pressure systems. As a result, the southwest monsoon starts to initiate a retreating monsoon around October. Not clear. It begins to withdraw from the northern parts of the country first. Retreating monsoon relates to clear skies and a slight rise in the temperature. By early November, the low-pressure situation shifts to the Bay of Bengal, creating cyclonic disturbances. The cyclone then hits the eastern coastal regions, usually causing tremendous damage.

Monsoons as a Unifying Bond

Monsoons are considered to be a unifying bond in the country. They are marked with local and seasonal variations, and the entire country looks ahead to their arrival. The agricultural sector solely depends on the monsoon season. India is an agricultural-centric country. Hence, monsoons and rainfall are necessary for India.

Definition of Weather in Climate Chapter Class 9 Notes

Weather, as a term, denotes the atmospheric conditions of a particular place for a day or a few hours. It depends on wind speed, humidity, temperature, and many more.

Difference Between Climate and Weather in Climate Chapter Class 9 Notes

The components and variables of climate and weather are the same, but still, there are some differences between the two. The weather conditions of a peace deal with the atmospheric conditions of each day of that particular place. On the other hand, the climate of a location is the average weather condition for 30 years or more. Weather is quite changeable, but the climate has been a standard concept for a while. Both weather and climate are standard concepts. Elaborate.

Factors that Control the Climate of a Place

The below-given factors affect the Climate of a geographical region.

• Latitude – the places which are near the equator get direct sun rays throughout the year. Here, the temperature remains high throughout the year. However, the places near the poles receive slanting sun rays and have low temperatures.
• Altitude – the temperature decreases by 6 degrees every 1 km from the sea level and this is known as the average lapse rate.
• Distance from the sea – the places near the seas have moderate climates. But the regions which are away from the seas have extreme weather climates. This happens because of the two types of winds: land breeze and sea breeze.
• Relief features – the presence of some significant relief features help shape a particular region’s Climate. Such as? Give examples.
• Humidity – the humidity of a region is affected by its distance from the sea.
• Ocean currents – if the cold ocean currents circulate near the seashore, you will have more excellent climatic conditions. Define excellent climatic conditions.

Factors Affecting India’s Climate

The following aspects have a direct impact on India’s climatic condition.

• Latitude – places in the northern parts of India have a cold climate while places in the southern parts experience warmer climes.
• Altitude – the places on the Himalayan range’s slopes have colder climates than those on the plains.
• Presence of winds – in the northwest part of India, the local winds stay during summer. It controls the climatic conditions of that region.
• Relief features – whether plain land, located on the hills or the plateaus determine the climatic conditions of a place. Check the grammar of this sentence. Consider, ‘location of a place on the plains, on the hills, or on the plateaus determine the climatic conditions of a place.

Indian Monsoon in Climate Notes

Monsoon wind is a seasonal wind that prevails in South and Southeast Asia. It is derived from the Arabic word ‘mausim’ which means monsoon. From May to September, it blows in the northeastern direction bringing heavy rainfall to the Indian subcontinent.

Formation of Monsoon in Climate Class 9 Notes

The monsoon winds are generated by the differences in the land and sea heating and cooling rates. Which cools faster and why? During the summer, the high-pressure situation forms in Madagascar and the low pressure in the Tibetan plateau. Because of the two pressure cells, the winds enter the two branches of India, the Bay of Bengal and the Arabian Sea, eventually causing heavy rainfall. The monsoon hits the Kerala coastal regions at the end of May, bringing heavy rainfall.

Seasons of India

There are four seasons in India: summer, rain, transition period, and winter. During the summer season, the local hot winds are known as loo. The monsoon winds bring rain in the rainy season. In the period of transition, a mild climate prevails. During the winter, snowfall occurs in the northeastern parts of India.

Did You Know?

India’s climate is extreme. Mawsynram in Meghalaya receives 10,000 m of rainfall in a year. Churu of Rajasthan is the hottest place in India. How much rainfall does Churu receive? Please mention, if it’s a comparison between the wettest and driest places in India. The temperature here reaches 50 degrees during the summer season.