Role of Tibetan plateau : The Tibetan plateau is located more than 4500 kilometre above sea level with a length of 2000 kilometre and with a width of 600 kilometre in the west and 1000 in the East.The plateau is considered to be one of the key factors in the development of monsoon. The Tibetan plateau exerts its influence as a mechanical behaviour as well as high heat plateau. An anticyclone appears in upper troposphere due to latent heating over the Tibetan plateau. It generates an area of rising air, during its Ascent the year spread outwords and gradually sinks over the equaltorial part of the Indian Ocean. it piks up moisture from the Indian Ocean and causes rainfall in India and adjoining countries.
Characteristics of monsoonal rainfall
- Rainfall from Southwest monsoons is seasonal in character which occurs between June and September.
- Monsoonal rainfall is largely governed by relief or topography. for instance the windward side of the Western Ghats registers a rainfall of over 250cm the heavy rainfall in the North Eastern states can be attributed to their Hill ranges and the Eastern Himalayas.
- The monsoon rainfall has a declining trend with increasing distance from the Sea Kolkata receives 119cm during the Southwest monsoon period, Patna 105 centimetre, Allahabad 76 centimetre,Delhi 56 centimetre and Bikaner 24 centimetre.
- The monsoon rains are characterized by 'breaks' these breaks in rainfall are related to the cyclonic depression formed at the head of the Bay of Bengal and their crossing into the mainland. the frequency of such depressions is 2 to 4 per months from June to September.
- The summer rainfall comes in a heavy downpour leading to considerable run of and soil erosion.
- Monsoon is a pivot of the agrarian economy of India because over three fourths of the total rain in the country is received during the Southwest monsoon season.
- Its special distribution is quit uneven ranging from 12 cent in western Rajasthan to more than 400cm in the Meghalaya.
- The beginning of the Rains sometimes is considerable delete over the whole are a part of the country the range sometimes and considerable e earlier than useful causing great Tamas to standing crops and making the sowing of winter crops difficult this is why monsoons are extremely unproductive and uncertain.
