Laboratory measurements of the microwave opacity and vapor pressure of sulfuric acid vapor under simulated conditions for the middle atmosphere of Venus

摘要: Abstract Microwave absorption observed in the 35- to 48-km-altitude region of Venus atmosphere has been attributed presence gaseous sulfuric acid (H2SO4) that region. This motivated laboratory measurement microwave at 13.4- and 3.6-cm wavelengths from H2SO4 a CO2 under simulated conditions for As part same experiments, upper limits on saturation vapor pressure have also determined. The measurements made 1- 6-atm range, with temperatures 500 575°K range. Using theoretically derived temperature dependence, best-fit expression 13.4-cm wavelength is 9.0 × 10 9 q(P) 1 2 T −3 ( dB km −1 ), where q number mixing ratio, P atmospheres, degrees Kelvins. 4.52 1010q(P)0.85T−3 (dB km−1). inferred above liquid corresponds ln p = 8.84 − 7220/t (in atm) These results suggest abundances order 15 30 ppm could account by radio occultation experiments 13.3- wavelengths. They such would correspond existing or 46- 48-km which correlates cloud base. It suggested future 3-cm range will provide additional tools monitoring variations abundance via astronomical observations.