A Non-Equilibrium Model of Hemispheric Mean Surface Temperature

A simple mean hemispheric temperature model has been constructed in the form of a differential equation that is a function of three independent variables: carbon dioxide content of the air, volcanic ejecta, and anthropogenic particulate pollution. This model appears to simulate the behavior of Northern Hemisphere mean temperatures as well as they are known and gives a different pattern of behavior for the Southern Hemisphere. By more completely accounting for those anthropogenic processes that produce both lower tropospheric aerosols and carbon dioxide (such as fossil fuel burning and agricultural burning), the authors calculate an expected slight decrease in surface temperature with an increase in CO sub(2) content. Although an invariant solar constant was assumed, an unmistakable 20-25 yr periodicity was found in the difference between the calculated and observed direct solar flux reaching the Earth's surface, which suggests a definite, but small, periodic variation in the solar constant.