Nature of the Ultraviolet Absorber in the Venus Clouds: Inferences Based on Pioneer Venus Data

Several photometric measurements of Venus made from the Pioneer Venus orbiter and probes indicate that solar near-ultraviolet radiation is being absorbed throughout much of the main cloud region, but little above the clouds or within the first one or two optical depths. Radiative transfer calculations were carried out to simulate both Pioneer Venus and ground-based data for a number of proposed cloud compositions. This comparison rules out models invoking nitrogen dioxide, meteoritic material, and volatile metals as the source of the ultraviolet absorption. Models involving either small (∼1 micrometer) or large (∼10 micrometers) sulfur particles have some serious difficulties, while ones invoking sulfur dioxide gas appear to be promising.

[1]  J. Mihalov,et al.  Electron Observations and Ion Flows from the Pioneer Venus Orbiter Plasma Analyzer Experiment , 1979, Science.

[2]  C. Russell,et al.  Absorption of Whistler Mode Waves in the Ionosphere of Venus , 1979, Science.

[3]  D. Hunten,et al.  Clouds of Venus: A Preliminary Assessment of Microstructure , 1979, Science.

[4]  D. Diner,et al.  Temperature, Cloud Structure, and Dynamics of Venus Middle Atmosphere by Infrared Remote Sensing from Pioneer Orbiter , 1979, Science.

[5]  M. Tomasko,et al.  Absorption of Sunlight in the Atmosphere of Venus , 1979, Science.

[6]  J. Pollack,et al.  Venus Lower Atmospheric Composition: Analysis by Gas Chromatography , 1979, Science.

[7]  J. Hansen,et al.  Orbiter Cloud Photopolarimeter Investigation , 1979, Science.

[8]  D. Crisp,et al.  Vertical extent of zonal winds on Venus , 1978 .

[9]  D. W. Strecker,et al.  Properties of the clouds of Venus, as inferred from airborne observations of its near-infrared reflectivity spectrum , 1978 .

[10]  J. Pollack,et al.  Estimates of the Climatic Impact of Aerosols Produced by Space Shuttles, SST's, and other High Flying Aircraft , 1976 .

[11]  B. Hapke,et al.  Evidence for an Elemental Sulfur Component of the Clouds from Venus Spectrophotometry , 1975 .

[12]  B. Hapke,et al.  Relative Spectrophotometry of Venus from 3067 to 5960 Å , 1975 .

[13]  R. Turco,et al.  Photodissociation rates in the atmosphere below 100km , 1975 .

[14]  G. C. Augason,et al.  Aircraft observations of Venus' near-infrared reflection spectrum: Implications for cloud composition , 1974 .

[15]  J. W. Hovenier,et al.  Interpretation of the polarization of Venus , 1974 .

[16]  A. T. Young.  Are the clouds of venus sulfuric acid , 1973 .

[17]  B. Savage,et al.  Ultraviolet photometry from the orbiting astronomical observatory. III - Observations of Venus, Mars, Jupiter, and Saturn longward of 2000 A. , 1972 .

[18]  James A. Weinman,et al.  Radiative Properties of Carbonaceous Aerosols , 1971 .

[19]  D. M. Treherne,et al.  The optical constants of graphite , 1966 .

[20]  W. Spear,et al.  Photogeneration of charge carriers and related optical properties in orthorhombic sulphur , 1966 .

[21]  P. Warneck,et al.  Ultraviolet Absorption of SO2: Dissociation Energies of SO2 and SO , 1964 .

[22]  K. F. Palmer,et al.  Optical constants of sulfuric Acid; application to the clouds of venus? , 1975, Applied optics.

[23]  Kent F. Parmer.  OPTICAL CONSTANTS OF SULFURIC ACID , 1974 .