Application of the spectrally integrated Voigt function to line-by-line radiative transfer modelling

- The spectrally integrated Voigt function is applied to radiative transfer.
- An algorithm for the rapid and accurate computation of the integrated is described.
- The traditional line function is replaced improving efficiency and accuracy.
- The efficient computation of radiance is enabled at reduced spectral resolution.
- Computational testing and an error analysis illustrate algorithmic performance.

We show that a new approach based on the spectrally integrated Voigt function (SIVF) enables the computation of line-by-line (LBL) radiative transfer at reduced spectral resolution without loss of accuracy. The algorithm provides rapid and accurate computation of area under the Voigt function in a way that preserves spectral radiance and, consequently, radiant intensity. The error analysis we provide shows the high-accuracy of the proposed SIVF approximations. A comparison of the performance of the method with that of the traditional LBL approach is presented. Motivations for the use and advantage of the SIVF as a replacement for conventional line function computations in radiative transfer are discussed.