Delta eddington
From Glossary of Meteorology
delta Eddington
An approximate technique for handling the complexity of shortwave radiative transfer in anisotropically scattering atmospheres.
The approximation is fairly accurate for transmitted and reflected irradiances provided the optical depth of the medium is greater than ≈ 3 and the absorption is weak. It is used mainly to speed up shortwave radiation computations in cloudy atmospheres.