Vertical distribution of water in the atmosphere of Venus - A simple thermochemical explanation

• Main Authors: Lewis, John S., Grinspoon, David H.
• Format: Other/Unknown Material
• Language: unknown
• Published: 1990
• Subjects: 91; Venus; Carbonic acid
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19900062894

Several lines of evidence concerning the vertical abundance profile of water in the atmosphere of Venus lead to strikingly unusual distributions (the water vapor abundance decreases sharply in the immediate vicinity of the surface) or to serious conflicts in the profiles (different IR bands suggest water abundances that are discrepant by a factor of 2.5 to 10). These data sets can be reconciled if (1) water molecules associate with carbon dioxide and sulfur trioxide to make gaseous carbonic acid and sulfuric acid in the lower atmosphere, and (2) the discrepant 0.94-micrometer water measurements are due to gaseous sulfuric acid, requiring it to be a somewhat stronger absorber than water vapor in this wavelength region. A mean total water abundance of 50 + or - 20 parts/million and a near-surface free water vapor abundance of 10 + or - 4 parts/million are derived.