An Efficient and Accurate Technique to Compute the Absorption, Emission and Transmission of Radiation by the Martian Atmosphere
Abstract
CO2 comprises 95 pct. of the composition of the Martian atmosphere. However, the Martian atmosphere also has a high aerosol content. Dust particles vary from less than 0.2 to greater than 3.0. CO2 is an active absorber and emitter in near IR and IR wavelengths; the near IR absorption bands of CO2 provide significant heating of the atmosphere, and the 15 micron band provides rapid cooling. Including both CO2 and aerosol radiative transfer simultaneously in a model is difficult. Aerosol radiative transfer requires a multiple scattering code, while CO2 radiative transfer must deal with complex wavelength structure. As an alternative to the pure atmosphere treatment in most models which causes inaccuracies, a treatment was developed called the exponential sum or k distribution approximation. The chief advantage of the exponential sum approach is that the integration over k space of f(k) can be computed more quickly than the integration of k_{upsilon} over frequency. The exponential sum approach is superior to the photon path distribution and emissivity techniques for dusty conditions. This study was the first application of the exponential sum approach to Martian conditions.
 Publication:

Mars: Evolution of Volcanism, Techtonics, and Volatiles
 Pub Date:
 1990
 Bibcode:
 1990mevt.conf..198L
 Keywords:

 Absorption Spectra;
 Aerosols;
 Carbon Dioxide;
 Infrared Absorption;
 Mars Atmosphere;
 Radiative Transfer;
 Atmospheric Composition;
 Dust;
 Emissivity;
 Infrared Spectra;
 Mars Environment;
 Near Infrared Radiation;
 Spectrum Analysis;
 Lunar and Planetary Exploration