What is Monsoon and what causes it?
Rui Ying
What is monsoon
Monsoon is seasonal wind. It can be both dry and wet, although the later is more widely known.
What causes monsoon?
Basic concept: Hadley cells and ITCZ
Hadley cell is tropical atmospheric circulation and intertropical convergence zone (ITCZ) is a low air pressure zone. ITCZ is very clear in a map of cloud or precipitation.
Monsoon is seasonal shift of air pressure bands.
In boreal summer, land is warming faster than ocean, which leads to the northward movement of ITCZ. This brings the trade wind with moisture which convert to precipitation.
In austral summer, ITCZ moves southward. This causes the wet season of Southern Australia and the dry season of Indian subcontinent.