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DISTRIBUTION PATTERN OF RAINFALL IN INDIA

17th May, 2022 Geography

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Context

  • The southwest monsoon has advanced over the Andaman and Nicobar islands, signalling the start of the four-month seasonal rains- India Meteorological Department.

 

Rainfall Distribution

  • The normal yearly rainfall in India is around 125 cm, yet it has incredible spatial variations. India is an immense country in geological terms, with different locales encountering totally different climatic circumstances. This is likewise reflected in the dispersion of rainfall in India.
  • A few areas experience extremely high precipitation and others get exceptionally meagre distribution. The distinction between the kept most noteworthy and least in India is around 1178 cm. Rainfall in India is unpredictable throughout the year, with an obvious stormy season over the vast majority of the nation beginning in about June and finishing off with September.
  • Portions of the western coast and northeastern India get over around 400 cm of rainfall yearly.
  • Rainfall is under 60 cm in western Rajasthan and connecting portions of Gujarat, Haryana and
  • Rainfall is low on the inside of the Deccan level, and east of the Sahyadri.
  • Snowfall is confined to the Himalayan district.
  • The yearly precipitation is an exceptional factor from one year to another.
  • The rainfall over India is unevenly distributed.Along with the uneven distribution, the annual rainfall is also highly variable. 

 

The distribution of yearly rainfall in various pieces of India shows below:

  • The rainfall diminishes as one action from Kolkata to Amritsar.
  • It shows a declining pattern towards inside from the waterfront regions on Deccan Level.
  • Northeastern parts get more rainfall than northwestern pieces of India.

 

The normal rainfall in India is 120 cm as per yearly information from the Meteorological/Climatological Department.

 

The areas of rainfalls are classified in India are below, there are four regions of rainfalls in India as follows:

 

Areas of Inadequate Rainfall in India

Andhra Pradesh, Karnataka and Maharashtra, Ladakh, and a large portion of western Rajasthan get rainfall below 50 cm. Jaisalmer in Rajasthan is the spot in India that gets the least rainfall.

 

Low Rainfall Areas in India 

Maharashtra, Gujarat, Karnataka, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, Punjab, Haryana, and Western Uttar Pradesh are regions having 50 to 100 cm of rainfall.

 

Medium Rainfall Areas in India 

Gujarat, east Tamil Nadu, northeastern Peninsula covering Odisha, Jharkhand, Bihar, eastern Madhya Pradesh, northern Ganga plain along the sub-Himalayas, and the Sachar Valley and Manipur, Rainfall between 100-200 cm.

 

Areas of high rainfall in India 

The most noteworthy rainfall happens along the west coast, on the Western Ghats, as well as in the sub-Himalayan regions in the upper east and the slopes of Meghalaya. Northeastern locales and the windward side of the Western Ghats experience a normal 400 cm of yearly rainfall. In the Brahmaputra valley and the connecting slopes, the rainfall is less than 200 cm.

The areas encountering 200-300 cm rainfalls have a place within this zone. Eastern India majorly covers this zone.

 

Pattern of yearly rainfall

Attributable to the idea of rainstorms, the yearly rainfall is exceptionally factored from one year to another. Fluctuation is high in the districts of low rainfall like pieces of Rajasthan, Gujarat and the leeward side of the Western Ghats. The rainfall dispersion in India is affected by the Thar Desert and the Himalayas. Temperature and strain changes over the Indian Ocean, the Arabian Sea, the Bay of Bengal and the southern piece of the Pacific Ocean likewise assume a critical part in the monsoon downpours over the country.

 

Area that receives 400 cm of rainfall in India

Mawsynram town of Meghalaya gets rainfall over 400cm. Northeastern districts and the windward side of the Western Ghats experience a normal of 400cm of yearly precipitation. Regions like Assam, Meghalaya, Arunachal Pradesh and sloping lots of the Western Ghats are host to tropical rainforests.

 

Distribution of rainfall regions in India

The average annual rainfall in India is 120 cm and the rainfall regions in India are classified in 4 regions:

  • Low rainfall region. 
  • Inadequate rainfall region
  • Medium rainfall region. 
  • High rainfall region. 

 

Medium Rainfall Region

Gujarat, east Tamil Nadu, northeastern Peninsula covering Odisha, Jharkhand, Bihar, eastern Madhya Pradesh, northern Ganga plain along the sub-Himalayas, and the Sachar Valley and Manipur, Rainfall between 100-200 cm.

 

Types of rainfalls in India

Rainfalls are classified into three main types based on Origin, they are

Convectional rainfall, Orographic or relief rainfall, Cyclonic or frontal rainfall. And another rainfalls are classified in three types based on Intensity, they are

  • Low rainfall– rate of rain is b/w 0 to 2.5 mm 
  • Moderate rainfall– rate of rainfall is b/w 2.6 mm to 7.6 mm
  • Heavy rainfall– the rate of rainfall is above 7.6 mm

 

Reasons behind distribution of rainfall in India

 The rainfall distribution in India will occur due to these reasons stated below:

  • The Bay of Bengal some portion of the South-West storm brings downpour. 
  • Distance from the Sea: Areas along the coast get more rainfall when contrasted with those areas which further away from the ocean. 
  • Wind Direction: Due to the Arabian Sea Branch blowing corresponding to the Aravalli Hills, Rajasthan gets inadequate rainfall.

 

Type of monsoons in India

In India the monsoons are classified into two types 

  1. Southwest monsoons
  2. Northeast monsoons

 

Southwest monsoons 

The Southwest monsoons are the primary monsoon, roll in from the ocean and fires advancing up India’s west coast toward the beginning of June. By mid-July, the greater part of the nation is shrouded in downpour. This progressively begins clearing from most places in northwest India by October.

Northeast monsoons 

The northeast monsoons influences India’s east coast during November and December. It’s a short however extraordinary storm. The provinces of Tamil Nadu, Karnataka, and Kerala get the greater part of their rainfall from the upper east storm, while the remainder of the nation gets the majority of its rainfall from the southwest rainstorm.

 

Read more about Monsoon in India: https://www.iasgyan.in/daily-current-affairs/monsoon

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