The Tibetan Plateau is a mass of uplifted table-land spread over a large area. Due to its average height of 4500 m, it is also known as the roof of the world. It is considered one of the key drivers of the monsoon system in South Asia. Monsoon refers to the seasonal reversal of wind directions. During summers, the Tibetan Plateau heats up and causes the air above it to heat up as well. This creates a low pressure region as the hot air moves upwards. In contrast, the air over oceans remain cool as oceans lose heat less rapidly than land. When the heated air rises to a significant height above the adjoining Himalayas, the air carrying moisture from the oceans rushes to replace it in the form of south-west monsoon winds. It encounters resistance in the topographical barriers of the subcontinent and thus causes rainfall.
Distribution of high and low pressure areas depend on both macro and micro factors. The macro factors include global distribution of heat through insolation. This creates latitudinal variations in air pressure. Pressure also decreases with increase in height. The Coriolis effect due to earth's rotation and the apparent shifting of the sun due to earth's revolution also cause shifts in pressure belts.
Local factors include local variations in temperature, distance from sea and topography. Warmer regions are expected to have low air pressure and colder regions are expected to have higher pressure. The winds always move from areas of high pressure to low pressure