Monsoon is the result of unequal distribution of land and water, Differential seasonal heating and cooling of continents and oceans.
Sun shines over Tropic of Cancer Brings low-pressure centres (Near Baykal Lake and Peshawar) due to high temperature.
Low Temperature in southern hemisphere brings high pressure centre over australia and indian ocean. Wind blow from high (ocean) to low pressure in asis (land).
Ferrel,s law and Coriolis force to turn these wind in south-westerly direction They bring moisture from Indian oceans to indian subcontinent yielding heavy rainfall.
Sun shines over Tropic of Capricorn. Brings High Pressure to center (near Baykal Lake and Peshawar) due to low temperatures. High temperature in southern hemisphere brings low pressure Centre over Australia and Indian ocean. Wind blow from high to low pressure in north easterly direction called Retreating monsoon.
Monsoon originated due to shifting of pressure and wind belts. Intertropical Convergence (ITC) formed due to convergence of NE and SE trade winds near equator. Northern and Southern branches of the ITC, known as the NITC and SITC respectively, create a belt of doldrums marked by equatorial westerlies.
NITC extended up to 30 degree N latitude covering south and SE-Asia and establishes Equatorial westerlies. It brings atmospheric depressions(cyclones) with heavy rainfall.
Due to southward shifting of sun, pressure and wind belts also shifts. Western cyclonic disturbances from Mediterranean Sea enter India from west in winter due to Westerly Jet Stream.
Northeast trade winds reestablished over south and SE Asia. These NE trades become winter monsoons called retreating monsoon and rains in Andhra and Tamil region.
For more Articles on Geography please visit geographicbook.com