Indian Climate I

Date: December 13, 2014

Indian Climate

The Seasons

Winters : (Cold Weather)

  • November-February

Temperature

  • Temperature fall (decreases) from South to North.
  • In January, the temperature is less than 150C in Punjab, Haryana, West UP, North Rajasthan and in Kashmir, Himachal, Uttarakhand and Sikkim its less than 100
  • Cold wave and frost is common.
  • Temperature of West coast is 1.70C more than East Coast.
  • Winters are less effective in Peninsular India. Because of sea winds there is less change in the temperature.

Pressure and Winds :

  • North-East flows from land to sea. So most the season is dry. North trade winds cause rainfall in Tamil Nadu as the winds come from sea towards land.
  • Week high pressure builds up over the Northern part of country because of which winds from North and North West part blows towards Ganga valley. Clear sky and low temperature.
  • Cyclonic disturbances are peculiarity in Northern plains from West and North West. This low pressure mechanism develops over Mediterranean sea and West Asia and enters India by means of Westerlies. They cause snowfall in mountain and rainfall in plains. The local name of such rainfall is ‘Mahavat’ and very beneficial for Rabi crops (wheat, grams). During winters Jet streams flows through South of Himalayas.

Summers (Hot Weather) :

  • Due to the apparent Northward movement of sun towards tropic of cancer, global heat belt shifts towards North.

March to May month

Temperature

  • Temperature increases regularly.
  • Till April, the average Maximum temperature in South peninsular is 400 In May Rajasthan, West UP, Delhi, South Punjab, Haryana average maximum temperature is 420C. Ganganagar district in Rajasthan had 540C maximum temperature recorded. In North India at some places the temperature recorded is 450-470C. Daily minimum temperature is 270-280C.
  • In peninsula due to sea breeze flow, the temperature is less. In East India and mountains the temperature eis low.

Pressure and Winds

  • In North India during summers, the pressure becomes low. With the end of May, there is a build up of low pressure area perpendicularly from Thar desert to Chota Nagpur plateau. The movement of wind is around this low pressure area.
  • In North India during day time, hot and dry Westerlies flow. These are called ‘Loo’. Their direct impact could be fatal. When the dry and hot winds meet wet sea winds, then there is several local storms which causes rainfall and hail as well. These are known as ‘Kaal Baisakhi’ in West Bengal and ‘Bordai Chilla’ in Assam. Those are useful for tea and Rice crops.
  • With the end of summers, there is pre monsoon showers in Karnataka, Kerala which is called ‘Cherry Bloosom’ or ‘Mango Showers’. These are useful for coffee and Mango.

Autumn Season

  • The apparent position of sun is over the equator till the end of September. This weakens the low pressure through which then moves towards South. This weakens the monsoon and retreat it. During Mid of October, the Jet Stream South branch starts flowing towards South of Himalayas.

Temperature – There is more fall of minimum temperature rather than maximum. This increases daily temperature difference. The temperature of Day is high and nights are cold. High temperature and humidity makes the season very tough. This is called ‘October heat’ with the end of October, the daily temperature of North India falls sharply.

Rainfall – With the beginning of November, the low pressure belt over North-West India shifts to Bay of Bengal. This is directly related to the low pressure cyclones which originates over Andaman Sea. These tropical cyclones are generally destructive. These generally effect the East delta region and brings heavy rainfall. The major position of rainfall received by coromandal coast by these cyclones and depressions.


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