The millimeter-wavelength sulfur dioxide absorption spectra measured under simulated Venus conditions

Abstract

Over 130 laboratory measurements of the 2–4mm wavelength opacity of sulfur dioxide in a carbon dioxide atmosphere under simulated conditions for the upper Venus troposphere (temperatures between 308 and 343K and pressures between 0.03 and 2bar) have been made. These measurements along with the centimeter wavelength measurements by Steffes et al. (Steffes, P.G. et al. [2015]. Icarus 245, 153–161) have been used to empirically assess existing formalisms for sulfur dioxide opacity in a carbon dioxide atmosphere (Fahd, A.K., Steffes, P.G. [1992]. Icarus 97(2), 200–210; Suleiman, S.H. et al. [1996]. J. Geophys. Res.: Planets 101(E2), 4623–4635). The Van Vleck and Weisskopf Model (VVW) used by Fahd and Steffes with the JPL rotational line catalog (Pickett, H. et al. [1998]. J. Quant. Spectrosc. Radiat. Transfer 60(5), 499–890) was found to fit 85.88% of all 500 measurements within the 2-sigma uncertainty. This work will improve the confidence in retrievals of the atmospheric abundance of sulfur dioxide from millimeter-wavelength observations of the Venus atmosphere.