Entropy and climate. I: ERBE observations of the entropy production

This paper introduces an approximate method for estimating the global distributions of the entropy fluxes Howing through the upper boundary of the climate system, and provides an estimate of the entropy exchange between the earth and space and the entropy production of the planet. The entropy fluxes are those associated with the exchange of radiation between the earth and space and a specific method is described to derive these entropy fluxes from available measurements of the earth's radiation budget. The distribution of these entropy fluxes and the entropy production derived from these fluxes differ in significant ways from those reported previously. The major source of these differences arises from the incorrect estimate of entropy exchange associated with reflected solar radiation in these earlier studies. This problem is overcome by the application of a simple physical model for the entropy exchange. Radiative-transfer simulations of the entropy exchange demonstrate that this model reasonably approximates the entropy exchange associated with reflected solar radiation, and that the long-wave fluxes of cntropy arc closely approximated by the equivalent black-body entropy flux, Entropy fluxes calculated from the Earth Radiation Budget Experiment measurements show how the long-wave entropy flux densities dominate the total entropy fluxes at all latitudes compared with the entropy Hux densities associated with reHected sunlight, although the short-wave flux densities are important in the context of clear sky-cloudy sky net entropy flux differences. It appears from the analysis presented in thi