Origin Of The Monsoon

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Origin of the Monsoon:

  1.   Classcial Theories:
  1. Halley’s Thermal concept: Indian monsoon is because of contrast between Indian Subcontinent and adjoining Indian Ocean. Halley’s theory, suggested in 1686, considers the summer monsoon to be a regional phenomenon.
  2. Aerological concept: This was suggested by R. Scherhag in 1948. According to this theory, monsoon circulation develops due to changes in air temperature at all levels over the Indian Subcontinent and adjoining Indian Ocean.

 

  1.  Modern theories:
  1. Dynamic Theory: Flohn (1951) according to Flohn, the monsoon is a global phenomenon due to global shift in pressure belts. The shift in pressure belts bring the ITC much more into the northern margin is around 30 degrees north over the Indian subcontinent. This brings the SE trades over the Indian subcontinent as south westerly monsoons. Similarly, the shift in pressure belts globally when it is winter for the N. Hemisphere pushes the ITC to a little more south of the equator. This brings the sub- tropical high on to the southern slopes of Himalayas and hence the NE trades blow from northeast to southwest as northeast monsoons.

 

  1. Tibet and Easterly Jet: Dr. P. Koteshwaram and Flohn concluded that heating of Tibet in summer strengthens the monsoonal circulation with an Average height of 4Kms above the MSL, Tibetan surface is warmed in summer and generates ascending warm air. The air turns to its right and sinks over the Arabian sea and joins the southwesterly  winds there by strengthening the monsoon. This circulation is part of the tropical easterly jet stream.

 

  1. Role of Sub- Tropical westerly Jet: The sub-tropical westerly jet normally located on the south slopes of Himalayas and the northeast plains disintegrates in summer due to intense heating of the northern plains and the global shift in pressure belts to the north in summer of the northern hemisphere. This facilities the onset of the monsoon over india by facilitating the development of the monsoon trough.

 

  1. The Somali Jet: The offshore areas of Somalia develop clod waters due to upwelling giving birth to the Somali current. The cold waters led to low temperature along Somali coast ( 15 degrees centigrade) whereas along Mumbai, the temperature is 30 degrees cent centigrade. This thermal gradient leads to development of the Somali jet stream blowing from western Arabian sea to the eastern Arabian sea. This adds moisture bearing winds to the southwest monsoon.

 

  1. The Monsoon trough: This is the ITC which forms as a huge gash of low pressure from the desert of Arabian to Bay of Bengal. This covers the northern plains and induces the SE trades to cross the equator and give birth the south westerly winds.

 

  1. El Nino: The development of El Nino conditions influence the monsoon. During  El Nino, the southern oscillation (i.e., the differences in pressure between port  Darwin and Tahiti, French Polynesia). If the southern oscillation is negative, Darwin pressure is higher than Tahiti due to high pressure over Australia, western pacific and adjacent Indian ocean. The high pressure conditions also cover the Indian ocean and the landmass of peninsular India. This prevents the movement of southeast trades towards the landmass of India. If the southern oscillation is positive, Tahiti pressure is more than that of Darwin. Low pressure is over North Australia and over adjacent Indian Ocean. This induces northward movement of southeast trades and hence strengthens monsoonal circulation. The combination of El Nino current (which appears as a warm saline current along the west coast of S. America replacing the cold Humboldt Current during a negative El Nino) and the southern oscillation is caused ENSO.

 

Onset of Monsoon

The summer monsoon over the Indian subcontinent first arrives over Kerala situated at the southern tip of the Indian Peninsula around 1st June with a standard deviation of about 7 days. The arrival of the monsoon over the region is noticed by wide spread persistent and heavy rainfall replacing the occasional pre-monsoon rains.

 

Retreat Of Monsoon

This  lasts between September and end of December. This is the season of retreating monsoons. The monsoon trough over the northern plains weakens and begins to shift southward. The retreating monsoon brings rain to coastal Tamil Nadu, Krishna- Godavari delta, region west of Aravallis and to northeast India. The retreat of the monsoon begins on 1st September (i.e., in Rajasthan), 15th September in Punjab- Haryana plains, 10th October from Ganges plains, 1st December from Tamil Nadu and by 15th December, the southwest monsoon withdraws from india completely. The retreating monsoon brings rainfall to AP south of Krishna delta and Tamil Nadu. The rainfall in Tamil Nadu in October/November, is 38.25 cms which is about 39% of its annual rainfall while for coastal Tamil Nadu it is 50% of the annual.

This is the season for tropical Cyclones-2/”>Cyclones that affect the Indian landmass. Cyclones that affect the east coast and the west coast from in the southern portions of the Bay of Bengal, particularly during the retreating monsoon season. Maximum number of that form in the Bay of Bengal form in November. More number of cyclones form in the bay of Bengal than the Arabian sea.

 

 

 

 



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The monsoon is a seasonal wind pattern that occurs in many parts of the world. It is characterized by a change in wind direction and a change in rainfall. The monsoon is caused by the difference in temperature between the land and the ocean. During the summer, the land heats up more quickly than the ocean. This causes the air above the land to rise, and cooler, moist air from the ocean to move in to replace it. This is known as an onshore flow.

The onshore flow of moist air from the ocean is what causes the monsoon rains. The amount of rain that falls depends on the strength of the onshore flow and the amount of moisture in the air.

Another factor that affects the monsoon is the position of the Intertropical Convergence Zone (ITCZ). The ITCZ is a band of low pressure that lies near the equator. It is where the trade winds from the Northern and Southern Hemispheres meet.

During the summer, the ITCZ moves northward over the Indian subcontinent. This brings warm, moist air from the Indian Ocean to the region. This is what causes the monsoon rains to begin.

The monsoon is a vital part of the Indian Climate. It provides much-needed rainfall for crops and helps to regulate the temperature. However, it can also cause flooding and other problems.

The following are some of the sub topics that are related to the origin of the monsoon:

  • The Intertropical Convergence Zone (ITCZ)
  • The trade winds
  • The difference in temperature between the land and the ocean
  • The onshore flow of moist air from the ocean
  • The amount of rain that falls
  • The monsoon rains
  • The monsoon climate
  • The monsoon’s impact on crops
  • The monsoon’s impact on temperature
  • The monsoon’s impact on flooding

The Intertropical Convergence Zone (ITCZ) is a band of low pressure that lies near the equator. It is where the trade winds from the Northern and Southern Hemispheres meet. The ITCZ is a major factor in the formation of the monsoon. During the summer, the ITCZ moves northward over the Indian subcontinent. This brings warm, moist air from the Indian Ocean to the region. This is what causes the monsoon rains to begin.

The trade winds are winds that blow from the east in the Northern Hemisphere and from the west in the Southern Hemisphere. They are caused by the difference in temperature between the equator and the poles. The trade winds are a major factor in the formation of the monsoon. They help to transport warm, moist air from the ocean to the land.

The difference in temperature between the land and the ocean is another major factor in the formation of the monsoon. During the summer, the land heats up more quickly than the ocean. This causes the air above the land to rise, and cooler, moist air from the ocean to move in to replace it. This is known as an onshore flow. The onshore flow of moist air from the ocean is what causes the monsoon rains.

The onshore flow of moist air from the ocean is what causes the monsoon rains. The amount of rain that falls depends on the strength of the onshore flow and the amount of moisture in the air. The stronger the onshore flow and the more moisture in the air, the more rain will fall.

The monsoon rains are a vital part of the Indian climate. They provide much-needed rainfall for crops and help to regulate the temperature. The monsoon rains also help to replenish the groundwater and prevent droughts.

The monsoon climate is characterized by a wet season and a dry season. The wet season occurs during the summer, when the monsoon rains fall. The dry season occurs during the winter, when the monsoon rains stop falling.

The monsoon’s impact on crops is significant. The monsoon rains provide much-needed water for crops. Without the monsoon rains, many crops would not be able to grow. The monsoon rains also help to control pests and diseases.

The monsoon’s impact on temperature is also significant. The monsoon rains help to cool the air and reduce the risk of heatstroke. The monsoon rains also help to improve air quality.

The monsoon’s impact on flooding is also significant. The monsoon rains can cause flooding, especially in low-lying areas. Flooding can damage crops, homes, and Infrastructure-2/”>INFRASTRUCTURE. It can also lead to loss of life.

The monsoon is a complex weather system that has a significant impact on the Indian subcontinent. It is a vital part of the Indian climate and provides much-needed rainfall for crops. However, it can also cause flooding and other problems.

What is the monsoon?

The monsoon is a seasonal wind pattern that occurs in many parts of the world, including Asia, Africa, Australia, and the Americas. It is characterized by a change in wind direction and a change in rainfall patterns.

What causes the monsoon?

The monsoon is caused by the difference in temperature between the land and the ocean. In the summer, the land heats up faster than the ocean. This causes the air over the land to rise, and the air over the ocean to sink. This creates a pressure difference, which causes the wind to blow from the ocean to the land.

What are the effects of the monsoon?

The monsoon has a significant impact on the climate of many parts of the world. It brings much-needed rainfall to many areas that would otherwise be dry. However, it can also cause flooding and other problems.

What are some of the benefits of the monsoon?

The monsoon provides much-needed rainfall to many areas that would otherwise be dry. This rainfall is essential for agriculture and other human activities. The monsoon also helps to regulate the temperature of the land and the ocean.

What are some of the challenges of the monsoon?

The monsoon can cause flooding, landslides, and other natural disasters. It can also disrupt transportation and other human activities. The monsoon can also lead to the spread of diseases.

How can we mitigate the risks of the monsoon?

There are a number of things that can be done to mitigate the risks of the monsoon. These include:

  • Building Dams and other infrastructure to control flooding.
  • Educating people about the risks of the monsoon and how to stay safe.
  • Investing in early warning systems so that people can prepare for the monsoon.
  • Planting trees and other vegetation to help absorb the rainfall.

The monsoon is a seasonal reversal of wind direction between the land and the ocean, particularly in the tropics. It is caused by the difference in temperature between the land and the ocean. In the summer, the land heats up faster than the ocean, causing the air above the land to rise. This creates an area of low pressure over the land. The air from the ocean, which is cooler and denser, flows in to fill this low pressure area. This is the monsoon wind.

The monsoon is a major factor in the climate of many parts of the world, including India, Southeast Asia, and Australia. It brings much-needed rain to these areas, which are otherwise dry for much of the year. The monsoon also plays a role in the distribution of rainfall in these areas.

The monsoon is a complex phenomenon, and there is still much that we do not understand about it. However, it is a vital part of the climate of many parts of the world, and its effects are felt by millions of people.

Here are some MCQs about the monsoon:

  1. The monsoon is a seasonal reversal of wind direction between the land and the ocean. True or False?
  2. The monsoon is caused by the difference in temperature between the land and the ocean. True or False?
  3. The monsoon is a major factor in the climate of many parts of the world, including India, Southeast Asia, and Australia. True or False?
  4. The monsoon brings much-needed rain to these areas, which are otherwise dry for much of the year. True or False?
  5. The monsoon also plays a role in the distribution of rainfall in these areas. True or False?
  6. The monsoon is a complex phenomenon, and there is still much that we do not understand about it. True or False?
  7. The monsoon is a vital part of the climate of many parts of the world, and its effects are felt by millions of people. True or False?

Answers:
1. True
2. True
3. True
4. True
5. True
6. True
7. True

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