Hadley cellread
Between the equator and 30°. Heated by the Sun, warm, moist air rises in the Intertropical Convergence Zone (ITCZ): low pressure, thunderstorms. High up, it heads towards the poles, cools and sinks around 30°: high pressure, dry air, great deserts. At the surface it flows back to the equator: these are the trade winds, deflected westwards by the Earth's rotation (Coriolis force).
Ferrel cellread
Between 30° and 60°. It is driven by the other two. At the surface, air moves towards the poles and the Coriolis force deflects it eastwards: these are the westerlies, which bring ocean storms to Europe. Around 60° it meets polar air at the polar front (low pressure) and rises.
Polar cellread
Between 60° and the pole. Very cold, dense air sinks over the pole (high pressure), then flows towards 60° at the surface: these are the polar easterlies. Warmed by contact with milder air, it rises at the polar front and returns to the pole high up.