Interpretation of Mariner 10 Infrared Observations of Venus

Abstract

The infrared radiometer experiment on Mariner 10 measured limb darkening curves for Venus in two spectral intervals, one near 11 µm and the other near 45 µm. In this paper, these are analyzed in terms of the vertical opacity profile at each wavelength over a limited altitude range, approximately 60?80 km above the surface of the planet. Accurate multiple scattering calculations are used to show that both opacity profiles are consistent with a model containing a cloud of 1.1 µm radius sulphuric acid droplets, and a small amount of water vapor. Profiles of particle number density and humidity vs height are presented.