Periodic Winds

• The direction of these winds changes with the change of seasons.
• Monsoon winds are the most important periodic winds.

Monsoon Winds:

• The word ‘Monsoon’ has been derived from the Arabic word ‘Mausim’ meaning season.
• The winds that reverse their direction with the change of seasons are called monsoon winds.
• During summer the monsoon winds blow from sea towards land and during winter from land towards seas.
• Traditionally these winds were explained as land and sea breezes on a large scale. But this explanation does not hold good now.
• Now a days the monsoon is generally accepted as seasonal modification of the general planetary wind system.
• The Asiatic monsoon is the result of interaction of both planetary wind system and regional factors, both at the surface and in the upper troposphere (see fig. 11.8)
• India, Pakistan, Bangladesh, Myanmar(Burma), Sri Lanka, the Arabian Sea, the Bay of Bengal, South-east Asia, North Australia, China and Japan are important regions where monsoon winds are prevalent.