ON THE EFFICIENCY OF THE ENGINE DRIVING THE ATMOSPHERIC CIRCULATION

Abstract

It is suggested that worthwhile results may be obtained by the use of a suitable form of the second law of thermodynamics for the calculation of the efficiency of the earth's surface and atmosphere, considered as the heat engine that is driving the large-scale atmospheric circulation. A relation is obtained connecting the rate at which the kinetic energy of the general circulation is dissipated by turbulence with the integral over the atmosphere of the net rate of absorption of radiation divided by the temperature at which it is absorbed. This is done on the apparently plausible assumption that any other terms in the atmosphere's entropy budget are relatively small. The method used is described, and its application is indicated with the aid of a sample calculation using illustrative data. It appears that the engine driving the atmospheric circulation is, from one point of view, more efficient than might be supposed.