A tropical climate that is impacted by the sub-tropical anticyclones and the inter-tropical convergence zone (ITCZ) is the monsoon climate of India. The monsoon climate in India can be divided into two main seasons, the summer monsoon (wet) season and the winter dry season. A monsoon is a seasonal change in the strongest, or prevailing winds of a coastal region. The summer monsoon is characterised by extremely heavy rainfall for very long periods of time over a four month time span from June to September and the winter season gives the opposite conditions for the rest of the year. In summer, the Himalayan areas can experience up to 80000mm of rain in a day whereas in Mumbai less than 50mm is received. This climate is due to many factors, most of them caused by the sub-tropical anticyclone and the movement of the ITCZ.
South East Asia has the most significant monsoon climate and is largely determined by three factors. Pressure differences which are caused by extreme heating and cooling of large land masses in relation to the smaller heat changes over the nearby sea area. These differences between the subtropical anticyclones and the surrounding air, determines the strength and direction of the associated winds. The second factor is the northward movement of the ITCZ during the northern hemisphere summer; and the third factor being the mountain barrier of the Himalayas (with many peaks over 8000m), which is high enough to influence the general atmospheric circulation in the region. Anticyclones are weather systems that are characterised by high pressure, low winds, clear skies and relatively high temperatures. They often originate between 30˚N and 30˚S of the equator (between the tropics) where there is intense insolation which causes warm air to rise by convection. As the warmer air is cooled due to it moving north in the Hadley cell, an area of high pressure is established around the tropics as the cooler air sinks.
The inter-tropical convergence zone (ITCZ)...