(b) Role of jet streams: M.T.Yin had given this concept stating that the burst of the monsoon depends upon the upper air circulation.Two prominent jet stream effect the monsoon winds.
The subtropical westerly jet stream, this jet streamdominates in winter time in upper troposphere circulation of the northern latitudes. It has a Global extent between latitude 25-32 degree north and can be located for South Asia at an elevation of about 12 kilometre. The jet stream is split owing to the 0 presence of Himalayan mountain system in its path. The winds tends to descend over North Western part of India resulting in atmospheric stability
- Equatorial easterly jet stream, this is a prominent feature of the upper air circulation during the Indian monsoon season appearing as a band of strong easterlies extending from South East Asia across the Indian Ocean and Africa to the Atlantic.
The Western and Eastern jet streams flows in the North and South of the Himalayas respectively. the Eastern jet becomes powerful and stationed and this results in more active South west monsoon.
