prevailing winds are the surface winds that blow between the subtropical high and the equator.
which surface winds blow between the subtropical high and the equator?
prevailing winds
the surface air that flows from these subtropical high-pressure belts toward the equator is deflected toward the west in both hemispheres by the coriolis effect. these winds blow predominantly from the northeast in the northern hemisphere and from the southeast in the southern hemisphere. because winds are named for the direction from which the wind is blowing, these winds are called the northeasterly trade winds in the northern hemisphere and the southeasterly trade winds in the southern hemisphere. the trade winds of both hemispheres meet at the doldrums.
trade winds
normally moving counter-clockwise, in the winter the indian ocean gyre reverses direction due to the seasonal winds of the south asian monsoon. in the summer, the land is warmer than the ocean, so surface winds blow from the ocean to the land. however, during the winter, these temperatures reverse, making the winds blow from the land to the ocean. because most of the air pressure gradient is retained behind the tibetan plateau, air pressure gradients over the indian ocean and the gyre are small. this results in winds of moderate strength, due to the protection from the full force winds blowing off the mongolian high pressure region. because of these moderate, dry winds, the winter monsoon season in the indian ocean region is the dry season for most of southern asia. due to this seasonal wind cycle, the currents of the indian ocean, which make up the indian ocean gyre, are directly affected, causing reversal.
indian ocean gyre