Trade winds

Near the surface, air flows back towards the equatorial low-pressure belt as the trade winds.

At the surface, the north-east trade winds approach this belt from the northern hemisphere and the south-east trade winds approach from the southern hemisphere. Where these winds converge, air is forced upwards.

In the tropics, converging trade winds near the Intertropical Convergence Zone (ITCZ) encourage air to rise. This rising air is part of the Hadley-cell circulation and produces thunderstorms, some of which can develop into an organised tropical storm when conditions are suitable.