The Full-Spectrum Correlated-K Distribution and Its Relationship to the Weighted-Sum-of-Gray-Gases Method

Abstract

Abstract A new Full-Spectrum correlated-k distribution has been developed, which provides an efficient means for accurate radiative transfer calculations in absorbing/emitting molecular gases. The Full-Spectrum correlated-k distribution can be used together with any desired solution method to solve gray-medium radiative transfer equations for a small number of gray absorption coefficients, followed by numerical quadrature. It is shown that the Weighted-Sum-of-Gray-Gases model is effectively only a crude implementation of the Full-Spectrum correlated-k distribution approach. Within the limits of the Full-Spectrum correlated-k distribution model (i.e., an absorption coefficient obeying the so-called “scaling approximation”), the method is exact. This is demonstrated by comparison with line-by-line calculations for a one-dimensional CO2-N2 gas mixture with varying temperature and concentration fields.