‘The circulation of the atmosphere’ outlines the general model of the movement of air around the Earth. There are three circulation cells either side of the equator: the Hadley cell (nearest to the equator) and the polar cell, driven by specific temperature and pressure gradients, and the Ferrel cell between them. It describes global pressure patterns and the Coriolis effect, which results in south-westerly trade winds in the northern hemisphere and north-westerly trade winds in the southern. Also described are the Intertropical Convergence Zone, the polar easterlies, the westerlies, and how air moves around high- and low-pressure regions. The action of the surface winds also produces the various ocean currents.