ABSTRACT
In winter atmospheric pressure is high over central Asia and IndoPakistan, and low over the oceans to the east and south. The movement of air from the high to the low pressure areas gives westerly winds over north China and Japan, and north to north-east winds over India, the Bay of Bengal, the Philippines and parts of Indonesia. These winds are the winter monsoon. In summer low pressure exists over the continent and high pressure over the oceans. Air movement from the high towards the low pressure in that period gives southerly winds-south-west off the west coast of India, south in the Bay of Bengal, and south to south-east over China, Japan, the Philippines and Indonesia. These winds are the summer or southerly monsoon. The words winter and summer might seem inappropriate labels for the monsoons in the equatorial part of the region where there are no substantial changes in mean temperatures during the year. Alternatives such as north-east and s0uth-west, however, are less acceptable, for although they apply well enough over the Indian Ocean they are often meaningless for the land areas, because both monsoons vary greatly in direction from place to place.
