To understand the mechanism of monsoons the following facts are important

(i) The difference in the rate of heating and cooling of land and sea on a large scale. During summers a low pressure area develops on the Indian landmass while the seas around experience comparatively high pressure.

(ii) The shift of the position of the Inter-Tropical Convergence Zone. This is the equatorial trough normally positioned about 5°N of the equator, also known as the monsoon trough during the monsoon season.

(iii) The presence of high pressure area, east of Madagascar approximately at 20°S over the Indian Ocean. The intensity and position of this high pressure area affects the Indian monsoons.

(iv) The Tibetan high level plateau gets intensely heated during summers which results in strong vertical currents and formation of high pressure over the plateau at about 9 kilometers above sea level.

(v) The movement of the westerly jet to the north of the Himalayas and the presence of the tropical easterly jet over the Indian peninsula during summers.

Apart from this, it has also been noticed that changes in the pressure conditions over the southern Oceans also affect the monsoons.