The Trade Winds

This figure shows the tropical Pacific and surrounding land areas. The H and L symbols show regions of high and low air pressure, respectively. The dashed lines outline these regions. The solid arrows show the pressure gradient force, this force pushes air from high toward low pressure. The rotation of the Earth deflects the air toward the right in the northern hemisphere and the left in the southern hemisphere; this deflection, called the Coriolis force, is shown by the dashed arrows.

This figure shows the resulting trade winds as white arrows. Note that the winds flow generally westward along the equator, but there is some convergence, or tendency for the winds to also flow toward the equator. The zone where the winds come together is known as the "intertropical convergence zone (ITCZ); it is an area where tropical storms (hurricanes) can form. This zone shifts with the seasons, to the north during the northern hemisphere summer and the south during the southern hemisphere summer.

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