Trade Winds

The trade winds are a persistent band of easterly winds that blow toward the equator in both hemispheres, covering most of the earth between 25 degrees N and 25 degrees S latitude. These winds [Page 1761]originate on the equatorial sides of subtropical high-pressure systems that exist over the tropical and subtropical oceans and represent a major component of the general circulation of the atmosphere. The high-pressure areas force air to move toward a belt of low-pressure near the equator called the doldrums. The air converging at the doldrums rises high over the earth, recirculates toward the poles, and sinks back toward the earth's surface to about 30 degrees latitude, thus completing a cycle. The surface air that flows from the subtropical highs toward the equator ...