Monday, June 01, 2009

Chasing the Monsoon: A Modern Pilgrimage Through India

By M H Ahssan

A monsoon is a seasonal prevailing wind that lasts for several months. The term was first used in English in India, Bangladesh, Pakistan, and neighboring countries to refer to the big seasonal winds blowing from the Indian Ocean and Arabian Sea in the southwest bringing heavy rainfall to the area. In hydrology, monsoon rainfall is considered to be that which occurs in any region that receives the majority of its rain during a particular season. This allows other regions of the world such as North America, South America, Sub-Saharan Africa, Australia and East Asia to qualify as monsoon regions. In terms of total precipitation and total area covered, the monsoons affecting the Indian subcontinent dwarf the North American monsoon, and the South Asian monsoon affects a larger number of people, owing to the high density of population in that part of the world.

India’s climate is dominated by monsoons. Monsoons are strong, often violent winds that change direction with the season. Monsoon winds blow from cold to warm regions because cold air takes up more space than warm air. Monsoons blow from the land toward the sea in winter, and from the sea toward land in the summer.

India’s winters are hot and dry. The monsoon winds blow from the northeast and carry little moisture. The temperature is high because the Himalayas form a barrier that prevents cold air from passing onto the subcontinent. Additionally, most of India lies between the Tropic of Cancer and the equator, so the sun’s rays shine directly on the land. The temperature can reach as high as 110oF during the Indian winter.

The summer monsoons roar onto the subcontinent from the southwest. The winds carry moisture from the Indian Ocean and bring heavy rains from June to September. The torrential rainstorms often cause violent landslides. Entire villages have been swept away during monsoon rains. Despite the potential for destruction, the summer monsoons are welcomed in India. Farmers depend on the rains to irrigate their land. Additionally, a great deal of India’s electricity is generated by water power provided by the monsoon rains.

Pakistan is much drier than India. The summer monsoon winds in India bring moisture from the Indian Ocean; Pakistan is north of the ocean and receives much less rain. The Thar Desert is on the border between India and Pakistan. It covers more than 77,000 square miles, about the size of Nebraska.

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