Monsoon

The major monsoon systems of the world consist of the West African and Asia-Australian monsoons. The inclusion of the North and South American monsoons with incomplete wind reversal has been debated.[4] The term was first used in English in British India (now India, Bangladesh and Pakistan) and neighbouring countries to refer to the big seasonal winds blowing from the Bay of Bengal and Arabian Sea in the southwest bringing heavy rainfall to the area.[5][6] The south-west monsoon winds are called 'Nairutya Maarut' in India. Etymology The English monsoon came from Portuguese monção, ultimately from Arabic mawsim (ﻢﺳﻮﻣ "season"), "perhaps partly via early modern Dutch monsun".[7] History Strengthening of the Asian monsoon has been linked to the uplift of the Tibetan Plateau after the collision of the Indian sub-continent and Asia around 50 million years ago.[8] Many geologists believe the monsoon first became strong around 8 million years ago based on records from the Arabian Sea and the record of wind-blown dust in the Loess Plateau of China. More recently, plant fossils in China and new long-duration sediment records from the South China Sea led to a timing of the monsoon starting 15–20 million years ago and linked to early Tibetan uplift.[9] Testing of this hypothesis awaits deep ocean sampling by the Integrated Ocean Drilling Program.[10] The monsoon has varied significantly in strength since this time, largely linked to global climate change, especially the cycle of the Pleistocene ice ages.[11] Timing of the monsoon strengthening of the Indian Monsoon of around 5 million years ago was suggested due to an interval of closing of the Indonesian Seaway to cold thermocline waters passage from the Pacific to the Indian Ocean which is believed to have resulted in an increased sea surface temperature in the Indian Ocean, which increased gyral circulation and then caused an increased intensity of the monsoon.[12] Monsoon clouds over Lucknow, Uttar Pradesh. Five episodes