RADIATIVE-TRANSFER MODELS OF THE NIGHT SIDE OF VENUS

Results of radiative-transfer computations are reported for a realistic model of the structure of the atmosphere and cloud layers of Venus, including Mie scattering for the cloud particles. A difference-equation algorithm for multiple scattering is used which is found to be of an accuracy and efficiency that compare favorably to the matrix-operator method. Calculated spectra are compared to ground-based observations of the night side of Venus. In order to obtain a fit, special parameters must be introduced to account for the CO2 far wing opacity (which may also reflect the presence of lines not in our database) and one or more unidentified strong absorption bands in the wavelength region near 1.71 μm. The fit then implies, for a region of average brightness: (a)_cloud particle densities close to those derived from the PV LCPS experiment; and (b) a depletion of water by a factor of about 4 with respect to PV results. For more accurate results, spectral data for conditions prevalent on Venus are urgently required. © 1990.