The aeolosphere and atmosphere of Venus

A self-consistent model of the Venus atmosphere that satisfies the multitude of existing observational data is proposed. Its main properties and the line of reasoning are described as follows. The radiative greenhouse effect cannot account for a surface temperature of 570°K. The blanketing must be due to dust; and the main source of energy, wind friction at the surface. The term ‘aeolosphere’ is proposed for the region between the surface and the clouds of Venus, where wind is responsible for grinding and raising the dust as well as for the heating. Self-consistency requires the opacity to be so high as to impose an adiabatic vertical lapse rate. The potential temperature in the aeolosphere must be nearly constant. Horizontal pressure gradients driving the wind are caused by climatic differences near the top of the dust clouds. The dust may consist of calcium and magnesium carbonates with impurities. Pressure estimates from CO2 bands and optical scattering point to the presence of two distinct reflecting layers, the visible cloud level at about 0.6 atm and 340°K, and an upper haze level at 0.08 atm and 234°K. In the visual and near infrared the upper haze is virtually transparent, owing to forward scattering. In the ultraviolet, and in the infrared beyond 1.4 microns, it is opaque. Vertical cross sections of the Venus atmosphere are constructed for 80, 40, and 20 per cent CO2. For 80 per cent CO2 the results are somewhat more consistent, yielding a pressure of 4.3 atm at 570°K at the surface, 22 km below the visible cloud level. Despite uncertainties in the H2O content, its amount is so small as to be nowhere condensable.