Effect of meridional circulation on the Venusian cloud layer: A model study

T. Imamura, G. L. Hashimoto

Research output: Contribution to journalArticlepeer-review


The meridional circulation can have a large influence on the cloud formation on Venus. In our model, the observed depression of near-infrared optical thickness at mid-latitude is reproduced as a result of the enhancement of cloud thickness at low and high latitudes. At high latitudes, the poleward transport of H 2 SO 4 -H 2 O droplets in the upper atmosphere makes a thick cloud, since most of the H 2 SO 4 -H 2 O droplets photochemically produced are transported poleward by the meridional circulation. At low latitudes, the large-scale ascent of the concentrated H 2 SO 4 vapor forms a dense lower cloud in accord with observations by entry probes. The equatorward transport of H 2 SO 4 vapor below the cloud by the meridional circulation and the sedimentation of droplets in the lower cloud leads to the accumulation of H 2 SO 4 vapor around the cloud base at low latitudes. The H 2 SO 4 vapor distribution agrees with the radio occultation observations. The middle cloud can be caused by the condensation of H 2 SO 4 vapor carried aloft by convective mixing.

Original languageEnglish
Pages (from-to)1569-1572
Number of pages4
JournalAdvances in Space Research
Issue number9
Publication statusPublished - Jan 1 1999
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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