Question: Indian monsoon is a unique phenomenon with distinct characteristics. Explain characteristics of monsoon. Discuss variation of monsoons on western and eastern coast of India.
Answer: Monsoons are seasonal winds that flow into the subcontinent, bringing with it moisture filled air causing rainfall. Monsoons are global variation of land and sea breeze.
Characteristics of monsoon
- Seasonal winds
Monsoons are not yearly phenomenon as they blow only during a certain time in the year. They are caused due to variation in pressure difference between Indian Ocean and Tibetan plateau. They withdraw after certain period.
- Reversing direction
During the summer months, the monsoons blow in South westerly direction as a result of westerlies. When winter arrives, the north-easterly winds push the winds out of the subcontinent. This is called wind reversal or post monsoon.
- Division of path
Monsoon blows in two branches viz Arabian sea branch and Bay of Bengal branch. The Arabian sea branch travels along Western coast while Bay of Bengal follows upto the north eastern hills.
Variation in Arabian sea branch and Bay of Bengal branch
- Arabian sea branch of monsoon flows perpendicular to Western Ghats. This allows clouds to directly ascend the slopes of the hills causing orographic rainfall. Thus western Ghats are more green.
- Bay of Bengal branch is parallel to eastern coast and Eastern Ghats. This makes them rain shadow to south western monsoons. Eastern ghats receive rainfall during north eastern monsoon.
- The western Ghats have many passes that allows monsoon to enter into the interior and move towards Gangetic plains and central hills. However region on the leeward side of Western Ghats get low rainfall.
- The Arabian sea branch does not experience any cyclonic activities whereas Bay of Bengal branch is vulnerable to changes due to cyclonic activities.
Monsoon is thus a unique climatic phenomenon experienced in Tropical regions of eastern hemisphere. Its importance on Indian economy and social life is immense.