Publication Abstracts

Knibbe et al. 1997

Knibbe, W.J.J., J.F. de Haan, J.W. Hovenier, and L.D. Travis, 1997: A biwavelength analysis of Pioneer Venus polarization observations. J. Geophys. Res., 102, 10945-10957, doi:10.1029/97JE00312.

A new method for analyzing Pioneer Venus polarimetry data on a pixel-wide basis is presented. Quasi-simultaneous observations at two wavelenths (550 and 935 nm) are combined and compared with results of multiple scattering calculations. In this manner, hypotheses about particle size distributions in the upper part of the Venus atmosphere are tested. Particles composed of a sulfuric acid solution are considered, and a distinction is made between large and small particles, called cloud and haze particles, respectively. Three model atmospheres have been investigated: (1) a single layer containing cloud particles, (2) a single layer containing a misture of cloud and haze particles, and (3) a two layer model with an upper layer composed of haze particles and a lower layer containing cloud particles. It is found that all three models agree with the observations at phase angles near 20°, but that the first model cannot be made to agree with the observations for phase angles near 90°. This confirms the presence of haze particles in the Venus atmosphere found earlier by Kawabata et al. [1980]. We find that the haze particles may be situated either above or mixed within the main cloud deck of Venus. We derived effective radii between 0.85 and 1.15 µm for the cloud particles, and effective radii of 0.2 or 0.3 µm for the haze particles. When the haze particles are situated above the cloud layer, the haze optical thickness can take values of up to 0.6 at 550 nm. When the haze particles are mixed with the cloud particles, their contribution to the total atmospheric scattering coefficient at 550 nm can become as large as 70%.

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BibTeX Citation

  author={Knibbe, W. J. J. and de Haan, J. F. and Hovenier, J. W. and Travis, L. D.},
  title={A biwavelength analysis of Pioneer Venus polarization observations},
  journal={J. Geophys. Res.},

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RIS Citation

ID  - kn09000a
AU  - Knibbe, W. J. J.
AU  - de Haan, J. F.
AU  - Hovenier, J. W.
AU  - Travis, L. D.
PY  - 1997
TI  - A biwavelength analysis of Pioneer Venus polarization observations
JA  - J. Geophys. Res.
VL  - 102
SP  - 10945
EP  - 10957
DO  - 10.1029/97JE00312
ER  -

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