A Computational Method for Spectral Molecular Absorption Using an Improved Voigt Algorithm.

摘要

Discussion of the fundamental elements and theory related to atmospheric transmittance is presented. A line-by-line transmission computer program is developed that utilizes the combined Doppler-Lorentz (Voigt) line broadening function. In addition a rapid algorithm to evaluate the Voigt function with a maximum relative error of about one part in 10,000 is described and a software package that processes the absorption line parameters necessary to calculate transmittance is given. The results of transmittance calculations for seven channels in the fifteen micrometer band, corresponding to the seven High Resolution Infrared Radiation Sounder (HIRS) channels, are furnished and the procedure to compute a band averaged transmission discussed. It is concluded that the Voigt algorithm developed here is an excellent computational procedure and the resulting transmittance program correctly calculates atmospheric transmission. (Author)