Climate Test - 12

• Rajasthan is situated in the North Western part of India. Climatically, Rajasthan is the driest part of India.
  
• Rajasthan falls under tropical and subtropical climate regions which is characterised by scanty rainfall
  
• Rainfall is mostly due to cloud busters which is less than millimetres. 
  

• Rajasthan receives scanty rainfall. The two main reasons are:
  
• South-east monsoon arising from Bay of Bengal loses its moisture by the time it reaches north-western part of India where Rajasthan is located.
  
• And the south-west monsoon arising from Bay of Bengal flows parallel to the Aravali mountains and reach north-east part of India.
  

• Winds that give maximum rainfall to India are south-west monsoon. These winds bring rains towards the end of the summer due to high pressure built in the Indian Ocean.
  
• These monsoon strikes Malabar Coast in the month of June and by November leaves the country. Most of the food production in India depends on these monsoons.
  

• The most common type of rainfall in India is relief rainfall.
  
• It is formed when air is raised over hills and mountains. As it rises the air gets cooled and condensed to form rain. It usually occurs in coastal areas.
  

The foothills of the Himalayas, Punjab-Haryana plain adjacent to the Himalayas, Rajasthan east of the Aravalli range, Uttar Pradesh, Bihar and northern part of West Bengal and Assam mostly experience dry winters. This is due to the fact that winds blow from northeast to southwest direction i.e. from land to the sea. Thus they are devoid of moisture.

• Cyclonic rainfall is caused due to Western disturbance, Nor'westers, and mango showers.
  
• Western disturbance is an extratropical storm originating in the Mediterranean Sea and that brings sudden winter rain to the Indian subcontinent.
  
• Nor’westers: The rising temperature in the summer results in low-pressure troughs and attracts cyclonic and North West winds which result in rainfall along with thunderstorms in the months of April and May. This is known as Kal Baisakhi or nor-westers.
  
• Mango showers: Pre-monsoon showers: Often called as mango showers are the rains that include light showers to heavy rains with thunders. These are due to the thunderstorm developed in the Bay of Bengal. These result in falling apart of mangoes from trees and hence called mango showers.
  

• Cold weather season is also called as winter. It starts in the month of November and ends in February. December and January months are the coldest months.
  
• This season is characterized by cold days and cold nights. Coldest month in India is January. Average temperatures in January range from 14 to 25 °C.
  

• India is blessed with a number of perennial rivers which flood with excessive rainfall. In India heavy rainfall is brought about by south-west monsoon. The annual rainfall of India is about 300–650 millimetres.
  
• This heavy rainfall is the reason for floods caused in India.