Class 9 Exam  >  Class 9 Notes  >  Social Studies (SST) Class 9  >  Important Points & Differences: Climate

Class 9 Geography Chapter 4 Notes - Climate

Important Points To Remember

1. Mango showers

  • Mango showers are pre-monsoon showers.
  • This phenomenon is observed in Kerala and coastal Karnataka.
  • The mango showers help in the early ripening of, mangoes.

Regions of Mango Shower and Kal BaisakhRegions of Mango Shower and Kal Baisakh

2. Kalbaisakhi

  • Kalbaisakhi means the violent black clouds of the month of Baisakh
  • This is the name given to the north-westerly and northerly winds in Bengal and Assam. These winds cause very heavy rains and distraction.

3. Chennai receives more rain in winter

  • The northeast winds pick up moisture while crossing Bay of Bengal. these winds are onshore in the winter season.
  • In the summer Chennai lies in the rain-shadow of the Western Ghats, moreover the winds are offshore, therefore receives less rainfall.

4. Break or burst of the monsoon:

  • The sudden approach of the moisture-laden winds is associated with violent thunder and lightning. 
  • This is known as the “break” or “burst” of the monsoons. The first ‘break’ of monsoons on the southwest coast of India is around 1st June.

5. Southern Oscillation

  • The pressure systems of the Pacific and Indian Oceans are interrelated. 
  • When the pressure is high in the Pacific, there is low pressure in the Indian Ocean. The winds move from high pressure to low pressure and vice-versa. 
  • This causes the shifting of winds across the equator in different seasons. this is known as the southern oscillation.

6. EI Nino Southern Oscillations 

  • A feature connected with Southern Oscillation is the EI Nino, a warm ocean current that flows past the Peruvian Coast, in place of the cold Peruvian current, every 2 to 5 years
  • The changes in pressure conditions are connected to the EI Nino, the phenomenon is referred to as ENSO (EI Nino Southern Oscillations).

7. Mawsynram receives the highest rainfall in the world:

  • Mawsynram is situated at the head of a funnel-shaped valley in the Khasi hills.
  • Its unique topographical location together with wind direction is responsible for causing the heaviest rainfall in the world.

8. The rainfall decreases from South to North 

  • The S.W. Monsoons originates from the Indian Ocean and divides into branches due to the shape of the Indian peninsular.
  • Trivandrum gets above 200 cm.
  • Whereas Delhi situated in the interior gets only about 50 cm.
  • The Arabian Sea branch strikes the Western Ghats and causes heavy rainfall.
  • Whereas another branch of the Arabian Sea monsoon blows parallel to the Aravallis. thus jodhpur gets less than 25cms of rain.

9. The Western Ghats receive more rain from the southwest monsoons than the Eastern Ghats because:

Map showing the position of Western and Eastern GhatsMap showing the position of Western and Eastern Ghats

  • The Arabian Sea branch of the monsoon is onshore.
  • These winds are forced to rise and cause heavy rains.
  • By the time these winds reach the east coast, most of the moisture is lost.
  • The winds are offshore, so they are given less rain.
  • The Eastern Ghats lies on the leeward/rain-shadow area, hence it gets less rain.

Indian would have been an arid land or dessert if there had been no phenomena of monsoons :

  • Indian receives 75 to 90% of the rainfall from the monsoons.
  • These monsoons winds occur due to the uneven heating of land and sea.
  • The mighty Himalayas check the two branches of southwest monsoons, the Arabian Sea branch and the Bay of Bengal branch. 
  • These, cover the whole of India thus preventing it from becoming a desert.

Question for Important Points & Differences: Climate
Try yourself:What is the primary factor responsible for the formation of monsoon winds in India?
View Solution

Important Differences Between:  

1. Equable Climate & Extreme Climate

Equable Climate

Extreme Climate

(i)   The climate is moderate, which is neither too hot in summer nor too cold in winter.

(ii)  The annual and daily range of temperature is low.

(iii) Those places situated near the sea coast enjoy equable climate e.g., Mumbai.

(i)  The climate is continental, which is very hot in summer and very cold in winter.

(ii) The annual and daily range of temperature is high.

(iii)Places situated in the interior have extreme climate e.g., Delhi.

 

2. Rainfall and Precipitation

Rainfall

Precipitation

(i) It is the only form of precipitation.

(i)  It is a broader term, it includes rainfall, sleet, snow and hail.

(ii) The water vapour condenses and changes into water and falls down like drops of rain.

(ii) The water vapour changes into different forms such as rainfall, snow, sleet or hail.

(iii) It involves a simple process i.e. ascending of air, colling and coming down like rain.

(iii) It is a more complex process.

(iv) Delhi receives rainfall.

(iv) Leh receives snowfall.

 

3. South-West Monsoons and Retreating Monsoons

South-West Monsoons

Retreating Monsoons

(i) These winds blow from June to September.

(i) These winds blow from October to November.

(ii) These are moisture-laden winds.

(ii) These winds originate from the land, hence are dry.

(iii) About 75 to 90% of the annual rainfall occurs during these months all over the country.

(iii)  These cause rainfall over the south-eastern coast when the winds pick up moisture from the Bay of Bengal.

(iv) It is the pleasant season of rains and greenery all over the country.

(iv) Due to clear skies, high temperature and high humidity, the weather is oppressively known as ‘October heat

  

4. Loo and Cold Wave

Loo

Cold wave

(i) It occurs in the hot weather season.

(i) It occurs in the cold weather season.

(ii) The hot and dry winds blow in the afternoon and may continue till mid Night

(ii) The western disturbances cause heavy snowfall in the western Himalayas which causes lowering of temperature on the plains.

(iii) It raises the day temperature. the temperature ranges between 40o C to50o C

(iii) the temperature falls by 55o C from the normal

 

5. South-West Monsoons and North-East Monsoons

South-West Monsoons

North-East Monsoons

(i) These are seasonal winds.

(i) These are trade winds.

(ii) Blow during summer, June to September.

(ii) Blow in winter, December to February.

(iii) Blow from sea to land.

(iii) Blow from land to sea.

(iv) Bulk to the annual rainfall received in India is brought by these winds.

(iv) These are dry winds, while crossing the Bay of Bengal they pick up moisture and give rainfall to the Coromandel Coast/Tamil Nadu coast.

(v) High temperature and low pressure.

(v) Low temperature and high pressure.

(vi) High humidity.

(vi) Low humidity.

 

Question for Important Points & Differences: Climate
Try yourself:Which of the following is a significant difference between South West Monsoons and Retreating Monsoons?
 
View Solution

The document Class 9 Geography Chapter 4 Notes - Climate is a part of the Class 9 Course Social Studies (SST) Class 9.
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FAQs on Class 9 Geography Chapter 4 Notes - Climate

1. What are the different climate classes mentioned in Class 9 geography?
Ans. The different climate classes mentioned in Class 9 geography are tropical, arid, temperate, and polar climates.
2. How do these climate classes differ from each other?
Ans. These climate classes differ based on factors such as temperature, precipitation, and vegetation patterns in each region.
3. What are some examples of countries that fall under each climate class?
Ans. Examples of countries that fall under each climate class include Brazil for tropical climate, Egypt for arid climate, Germany for temperate climate, and Greenland for polar climate.
4. How do climate classes impact the lifestyle and economy of people living in these regions?
Ans. Climate classes impact the lifestyle and economy by influencing agriculture, infrastructure development, and overall living conditions in each region.
5. Can climate classes change over time due to factors like global warming?
Ans. Yes, climate classes can change over time due to factors like global warming, leading to shifts in temperature and precipitation patterns in different regions.
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