The general circulation of the atmosphere is governed by the barotropic vorticity equation which contains a term for the angular velocity of the coordinate system in which the equation is studied. Traditionally the angular velocity term is taken constant but there is evidence that the time dependent terms in teh elliptic orbits that affect the earth should be taken into account in the equation.

The orbits that affect the atmosphere are the orbit of the earth about the center of the sun and because the earth follows the center of teh sun, the orbits of four planets. These are Jupiter, Saturn, Neptune and Uranus. The weather of the earth is affected by time variations in six different elliptical orbits. The time variations average out to zero over 2000 or 3000 years, the time it takes for an orbit5 to change the angular velocity of the solid earth so that it remains constant throughout the process.

The inclusion of the time variations in the basic vorticity adds new terms to the vorticiy equation that have periods of 28 days to 250 years and form the physical basis for long term changes in the general circulation. In addition the orbits of four planets affect the circulation of the sun and the general circulation of the earth's atmopshere furnish the link between sunspot activity and the earth's weather.