model of the mid-latitude segment of the Earth's wind circulation, proposed by William Ferrel (Ferrel, William) (1856). In the Ferrel cell, air flows poleward and eastward near the surface and equatorward and westward at higher altitudes; this movement is the reverse of the airflow in the Hadley cell (q.v.). Ferrel's model was the first to account for the westerly winds between latitudes 35° and 60° in both hemispheres. The Ferrel cell, however, is still not a good representation of reality because it requires that the upper-level mid-latitude winds flow westward; actually the eastward-flowing surface winds become stronger with height and reach their maximum velocities around the 10-kilometre (6-mile) level in the jet streams.