Monsoon Updates

Southwest Monsoon begins early Withdrawal/Retreat

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Retreat of Monsoon

Mains level : Not Much

The southwest monsoon rainfall, 7% more than normal, has started to withdraw.

What is Monsoon Withdrawal/Retreat?

  • In India, retreating monsoon is the withdrawal of south-west monsoon winds from North India.
  • The withdrawal is gradual and takes about three months.
  • With the retreat of the monsoons, the clouds disappear and the sky becomes clear. The day temperature starts falling steeply.
  • Monsoon rains weaken all over India except few southeastern states.
  • It is helpful in Rabi crop cultivation.

Factors affecting the retreat

Two predominant factors cause the phenomenon:

(1) Land topography

  • First, the low mountain range in each region runs from north to south, shielding it from west-bound winds that trigger summer monsoon.
  • After summer, the range aids in the ‘orographic lift’ or rising of east-bound air mass from a lower to higher elevation, forming clouds and resulting in rain.

(2) Atmospheric convection

  • The second factor is atmospheric convection or vertical movement of air.
  • As the earth is heated by the sun, different surfaces absorb different amounts of energy and convection may occur where the surface heats up very rapidly.
  • As the surface warms, it heats the overlying air, which gradually becomes less dense than the surrounding air and begins to rise.
  • This condition is more favorable from September to February because of the role played by sea surface temperature or water temperature.

Immediate factors influencing withdrawal

  • The withdrawal of the monsoon is based on meteorological conditions such as-
  1. Anti-cyclonic circulation (dry air that is the opposite of a cyclone)
  2. Absence of rain in the past five days and
  3. Dry weather conditions over the region

When does it occur?

  • The monsoon withdrawal is a long-drawn process and extends into mid-October, though the IMD considers September 30 to be the final day of the season over India.
  • The rain after that is categorised as “post-monsoon” rainfall.

Try this PYQ:

Q.The seasonal reversal of winds is the typical characteristic of:

(a) Equatorial climate

(b) Mediterranean climate

(c) Monsoon climate

(d) All of the above climates

 

Post your answers here.
6
Please leave a feedback on thisx

 

Also read:

Various terms related to Indian Monsoon

 

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Bibhu ranjan Khatua
Bibhu ranjan Khatua
9 days ago
Post your answers here." Read more »

a

Yash Anand
Yash Anand
9 days ago
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answer: B

Kiran Mai
Kiran Mai
9 days ago
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D

Shubham Pandey
Shubham Pandey
8 days ago
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c

RIturaj Singh Mourya
RIturaj Singh Mourya
8 days ago
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c

Raj Kumar
Raj Kumar
7 days ago
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C