Which three major circulation cells are typically recognized in each hemisphere?

• A. Hadley, Ferrel, Polar
• B. Polar, Ferrel, Hadley
• C. Trade Winds, Westerlies, Polar
• D. Jet, Monsoon, Polar

Answer: (A)

Global atmospheric circulation is organized into three overturning cells in each hemisphere: a Hadley cell near the equator, a Ferrel cell in the mid-latitudes, and a Polar cell near the poles. The Hadley cell forms because intense heating at the equator causes air to rise, move poleward at high levels, cool and sink around 30° latitude, and then return toward the equator at the surface as the Trade Winds. In the mid-latitudes, the Ferrel cell acts as a secondary circulation between roughly 30° and 60°, with air rising around 60° latitude and sinking around 30°, producing the Westerlies at the surface. Near the poles, the Polar cell involves cooling air sinking near the poles and rising around 60°, driving the Polar Easterlies at the surface. These three cells together explain the familiar pattern of surface wind belts—Trade Winds, Westerlies, and Polar Easterlies—and are the standard framework for global circulation in each hemisphere.