The 2D model system consists of the atmosphere and the grand surface. The model atmosphere is composed of ideal gas. The atmospheric constituent is assumed to CO only and its condensation and sublimation are not considered. The values of soil density, thermal conductivity and specific heat are constant each other. The surface topography is not considered.
The radiative transfer of CO atmosphere is calculated by a Goody narrow band model which considers 15 m band in infrared wavelength and 4.3, 2.7, 2.0 m band in near infrared wavelength. The values of absorption line intensities and widths in each band are same as those of Houghton (1986).
The radiative transfer of dust is calculated by -Eddington approximation model which considers two bands in infrared wavelength region (5-11.6, 20-200 m) and one band in solar wavelength region (0.1-5 m). The values of band width and optical parameters of dust (extinction efficiency, single scattering albedo, asymmetry factor) in each band are same as those of Forget et al. (1999) except in 11.6-20 m band which is not considered in our model.