Origin of the Monsoon

Last Updated: Thursday, July 23, 2009 - 22:12

Smita Mishra

Technically, monsoon is a seasonal prevailing wind that lasts for several months. But the significance and romance associated with it make monsoons more than a seasonal disturbance.
For a subcontinent that is dependent on the manna of this willful benefactor, monsoon means not just rains. It means life, food and survival for the entire South Asia that thrives on this blissful phenomenon.

Derived from Arabic word ‘Mawsin’ meaning season, South Asia without Monsoon would have been an extension of the central desert.

The tracking of Monsoon in ancient times made maritime trade easier. An unknown writer of the famous 1st century AD, Periplus of the Erythraean Sea and Pliny the Elder credit Greek navigator Hippalus with discovering the direct route from the Red Sea to India over the Indian Ocean by following the direction of the winds called monsoon( also known as Hippalus).

The traders of ancient Kalinga (Orissa), used to set out on their journey to Southeast Asian countries during the northeast monsoon and return during the southwest monsoon. The flow of wind and current was favourable for both the onward and return journey.

In the historical times and also during the Middle Ages both Arabs and Portuguese traders sailed in such a manner that they could reach the shores of India before the southwest monsoon and return only after the beginning of the northeast monsoon.

Although the exact cause of the origin of monsoons is not fully understood, no one disputes that building up of air pressure is one of the primary factors. In summers, a high pressure area lies over the Indian Ocean while a low pressure exists over the Asian continent because of the heating of the land. The moisture laden oceanic air masses move from the high pressure area over the ocean to the low over the continent, bringing rains.

During winter, the process is reversed and low pressure prevails over Indian Ocean while a high lies over the Tibetan plateau, so the air flows down the Himalayas and south to the ocean. The migration of trade winds and westerlies also contribute to the monsoons.

Monsoons are not just an Indian phenomenon. They also occur, though at a small scale, in equatorial Africa, northern Australia, and in the southwestern United States.

Almost half of the world`s population lives in areas under monsoon’s influence. Not just the rains but also their intensity and timings are of vital significance. If the rains are late and scanty, it means draught and famine and if they are more and last longer, it means flood and destruction.

Life in South Asia is gift of the monsoons. No one knows when these winds started blowing favourably on our lands, but thank God they did or in place of our green fields and blue rivers, a harsh merciless desert would have stretched across, with burning hot winds and rough fiery rocks, and an inexorable sun that no clouds could ever cover…



First Published: Thursday, July 23, 2009 - 22:12

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