Ferrel Cell

The Ferrel cell is the mid-latitude limb of the three-cell general circulation, between roughly 30 and 60 degrees latitude, sitting between the Hadley and polar cells. It is a thermally indirect, eddy-driven cell: surface air moves poleward and air aloft moves equatorward, the reverse of a heat-driven overturning, so it is maintained by momentum and heat transported by mid-latitude baroclinic eddies rather than by direct convection. Its surface branch produces the prevailing westerlies. Subsiding air on its equatorward edge reinforces the subtropical highs near 30 degrees, and rising air on its poleward edge marks the polar front and storm track.