Friday, December 19, 2014

Tibet Plateau affect on Indian Monsoons and its Meteorological Importance

Ques.7. Discuss the meteorological importance of Tibetan plateau and also its effect on Indian Monsoons?

Ans. The length of Tibet plateau in East West direction is around 2000 km. and its width in the east and west direction is 1000 km and 600 km respectively. Tibet plateau’s average height is around 4000 metre. Due to the height of Tibet plateau the amount of insolation received by it during the summers is very high when compared to surrounding landmass. So a low pressure develops over the Tibet plateau.

Impact of Tibet plateau on Indian Monsoons –

(1) Due to low pressure over Tibet plateau in summers pressure gradient develops which attracts trade winds from the Indian Ocean and these winds cause precipitation over India as they have picked up moisture from ocean.

(2) Hot Tibetan plateau in summers pushes air above in the troposphere. This air travel southwards and descend somewhere near the Mascarene Islands (Reunion, Mauritius and Rodrigues) through the Tropical Easterly Jet (TEJ) stream. Now this stream in the form of surface air is attracted towards the low pressure Intertropical Convergence Zone which during the summer time is shifted north wards and covers significant part of India. This surface air brings rain bearing winds to the Indian Peninsula thereby triggering monsoons.

Some experts have even said that Tibet plateau heating correlation with rainfalls over India holds well from May 20 to June 15, then from September 1 to October 15 it holds well. 

Meteorological Importance of Tibet Plateau –

Tibet plateau in winters is heavily covered with ice. Due to this high amount of ice Tibet plateau is also known as the third pole of the world.

It affect atmosphere in 2 ways –

(1) As a physical barrier
(2) As a heat source.

Tibet plateau obstructs the flow of extremely cold northern latitudes winds from entering the Indian subcontinent. As high pressure develops over Tibet plateau during the winters it has the potential to delay the onset of summer monsoon over Northern India due to the lowering of pressure gradient.

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