Most of the energy of sunlight penetrates the atmosphere and strikes the surface of the solid or liquid earth, where the wavelengths of light are absorbed and re-emitted as radiant heat. The primary heating of the atmosphere, therefore, is from below, from the ground and ocean surfaces. Column of rising air as it expands is the reason mountain tops are cold. Energy to do this work can come only from the air itself and it loses temperature accordingly. The major wind systems of the earth result from the fact that large masses of air around the earth's equator are forced to rise by bottom heating, causing air to rush in from high latitudes to fill the void.
Winds represent the working of a heat-distributing engine.
Heat is applied at the equator, the air moves up and then poleward, descends and returns equatorward along the earth's surface. This system is modified by properties of scale and by Coriolis force which is the force that diverts the air through it own momentum. Coriolis force deflects moving air or water to the right in the northern hemisphere and to the left in the southern hemisphere. Mountains and hills cause air masses that move toward them to rise. As an air mass rises and cools, water vapor condenses and falls to the earth.