An analytical solution for the albedo to solar radiation of a broken cloud field over a black, nonreflecting ocean surface is presented. The clouds are assumed to be infinitely long, nontransmitting bars, with any top and side albedos. Cloud-cloud shading and reflections are fully and analytically taken into account in the assessment of the contribution of the cloud sides to the cloud field albedo, while assuming, for this latter purpose only, the bi-directional reflectivity of the sides to be isotropic. The model is an explicit function of cloud thickness, width, and intercloud spacing for all solar zenith and azimuth angles. Results are presented in the form of an effective cloudiness in azimuthally averaged form and as a function of azimuth angle for different solar elevation angles, aspect ratios, amounts of cloudiness, optical depth, and albedo for single scattering. In order to show the dominant effect of the geometry over the radiation transfer in this case, we simulated the <Harshvardhan and Thomas, 1984> model, adding only the explicit solution for the cloud-cloud interaction. We then compared our results to theirs as well as to their Monte Carlo calculations, achieving a much better fit to the latter. The present model is neither more difficult to use than previous ones nor is it in need of refitting to data when more features are added or when optical properties of the cloud are changed. Tabular values of some necessary coefficients are given for independent use of the model. ¿ American Geophysical Union 1988 |