| School of Electrical and Computer Engineering | |
Recent observations of the millimeter wave (2.6 mm) emission from Venus have shown significant variations in its continuum flux emission (de Pater et al., 1991). Some of this change in emission may be attributed to variability in the abundance of Venus cloud consituents, specifically H2SO4 condensates. In order to evaluate this hypothesis, a knowledge of the dielectric properties of liquid sulfuric acid at millimeter wave frequencies (30 < f < 300 GHz) is needed. The dielectric constants can then be used to determine the expected absorptivity from such a condensate and hence the effect of H2SO4 droplets on the millimeter wave emission from Venus. Therefore we have performed laboratory measurements of the complex dielectric constant of liquid sulfuric acid between 30-40 and 90-100 GHz. The methodology and the results are reported in this paper along with a calculation of the absorption properties of H2SO4 droplets under Venus-like conditions. In addition, this paper discusses the effects of these condensates on the variation in the flux emission of Venus and compares the effect of H2SO4droplets with other absorbers in the atmosphere of Venus such as gaseous SO2. We conclude that this condensate does affect the brightness temperature of Venus and its effect cannot be omitted in future modeling of the atmosphere of Venus.