The Delta-Eddington Approximation for a Vertically Inhomogeneous Atmosphere

Flux continuity is enforced at each level, leading, as the mathematical essence of the problem, to a penta-diagonal system of linear equations for certain unknown constants. Fluxes (up, direct down, diffuse down, and net) are then predicted at each level.

Unphysical results of the model are examined in detail. Potential numerical instabilities in the solution are noted and corrected, and an extremely fast, well-documented computer code resulting from this analysis is described and listed. Actual computed fluxes are given for several test problems.