The circulation of air over the earth is largely due to the unequal heating of the surface. The global circulation of pressure and wind plays an integral role in the heat balance of the earth, as well as creating global ocean currents. The global circulation of the atmosphere transfers warm air from low latitudes towards high latitudes, and cold air from high latitudes towards low latitudes. This exchange keeps low latitude regions where there is a net gain of energy through the year from continually heating up and high latitudes from continual cooling due to a net loss of energy (see latitudinal variation in the radiation balance).

Geographers often use a three-cell model to describe the basic features of Earth's global patterns of wind and pressure. The basic assumptions of the model are:

• an Earth of uniform surface composition;