Evaluation of Upwelling Infrared Radiance in a Nonhomogeneous Nonequilibrium Atmosphere

The primary purpose of this study was to investigate the influence of vibrational nonequilibrium upon upwelling infrared radiance from the earth's atmosphere. Basic equations are presented for calculating the atmospheric transmittance, heating rates, and equilibrium and nonequilibrium upwelling radiances. By employing the Lorentz line-by-line model for spectral absorption, heating rates and upwelling radiances were calculated for equilibrium as well ·as nonequilibrium conditions in the spectral range of 4.6 μ CO and 3.3 μ 'CH4 bands. For the spectral range of CO fundamental band, the influence of different 1~arameters on the upwelling radiance was also investigated. The results indicate that for CO the assumption of LTE is not justified at tropospheric pressures and temperatures. For CH4 , however, the assumption is justified up to 60 kilometers. This information is very useful in developing an accurate data reduction scheme for the measurement of CO and CH4 concentrations in the atmosphere.