describe the main feature of retreating monsoon season of india?
Around September, with the sun fast retreating south, the northern land mass of the Indian subcontinent begins to cool off rapidly. With this air pressure begins to build over northern India, the Indian Ocean and its surrounding atmosphere still holds its heat. This causes the cold wind to sweep down from the Himalayas and Indo-Gangetic Plain towards the vast spans of the Indian Ocean south of the Deccan peninsula. This is known as the Northeast Monsoon or Retreating Monsoon.
While travelling towards the Indian Ocean, the dry cold wind picks up some moisture from the Bay of Bengal and pours it over peninsular India and parts of Sri Lanka. Cities like Madras, which get less rain from the Southwest Monsoon, receives rain from this Monsoon. About 50% to 60% of the rain received by the state of Tamil Nadu is from the Northeast Monsoon. In Southern Asia, the northeastern monsoons take place from December to early March when the surface high-pressure system is strongest. The jet stream in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across southern Asia, creating dry air streams which produce clear skies over India. Meanwhile, a low pressure system develops over South-East Asia and Australasia and winds are directed toward Australia known as a monsoon trough.
Main Characteristics of Retreating Monsoon
(i) October and November are the months of retreating monsoon.
(ii) During this season low monsoon trough becomes weak and is replaced by high pressure. Thus, monsoon begins to retreat. By the beginning of October it retreats completely from Northern Plains.
(iii) This period is the period of transition from hot rainy season to cold winter season. It is marked by clear sky, moist ground and high temperatures giving birth to October Heat.(iv) Low pressure trough shifts to Bay of Bengal. They give rise to cyclonic depressions which cause havoc on the eastern coasts-especially the coasts of Orissa, Andhra Pradesh and Tamil Nadu with very strong storms and rains.
2.the retreat of monsoon is marked by clear skies and cold weather
3.the low pressure pressure over the northern plain get transfered to bay of bengal
4.thickly populalated deltas of peninsular rivers get strucked by cyclones