Molecular Transmission Band Models for the Uniformly Mixed and the Trace Gases
TEXAS UNIV AT EL PASO DEPT OF ELECTRICAL ENGINEERING
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This report deals with the theory, development and validation of molecular transmission band models for the uniformly mixed nitric oxide methane, carbon monoxide, oxygen, and carbon dioxide, and for the trace nitrogen oxide, nitrogen dioxide, ammonia, and sulfur dioxide gases. The models were specifically designed for direct incorporation into the LOWTRAN atmospheric transmission code. The transmission function adopted for each gas, acting individually consists of a double exponential function defined by three gas dependent parameters and a single spectrally-dependent parameter. All of these parameters were determined optimally through a numerical procedure that generally incorporates line-by-line and measured transmittance spectra. The resulting nine models were defined at 5cm intervals throughout their absorber bands, for transmittance calculations of 20cm spectral resolution at typical atmospheric conditions. Averaged vertical mixing ration profiles for these gases were obtained for direct use with the 33-level standard atmospheric models in the calculation of slantpath transmittance. Comparisons are presented between line-by-line and measured transmittance spectra, and between these spectra, and model calculations using LOWTRAN 6.
- Atmospheric Physics