The subtropical ridge is a large belt of high pressure around 30ºN in the Northern Hemisphere and 30ºS in the Southern Hemisphere. It is characterized by mostly calm winds. Air flows out from its center toward the upper and lower latitudes of each hemisphere, creating both the trade winds and the westerlies.
- Webster's Online Dictionary Archived 2007-09-30 at the Wayback Machine
- Physical Geography - The Global Environment Archived 2006-09-23 at the Wayback Machine
- Winds and the Global Circulation System