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Published August 2015 | metadata_only
Journal Article

Distribution of sulphuric acid aerosols in the clouds and upper haze of Venus using Venus Express VAST and VeRa temperature profiles


Observations from Pioneer Venus and from SPICAV/SOIR aboard Venus Express (VEx) have shown the upper haze (UH) of Venus to be highly spatially and temporally variable, and populated by multiple particle size modes. Previous models of this system (e.g., Gao et al., 2014. Icarus 231, 83–98), using a typical temperature profile representative of the atmosphere (viz., equatorial VIRA profile), did not investigate the effect of temperature on the UH particle distributions. We show that the inclusion of latitude-dependent temperature profiles for both the morning and evening terminators of Venus helps to explain how the atmospheric aerosol distributions vary spatially. In this work we use temperature profiles obtained by two instruments onboard VEx, VeRa and SPICAV/SOIR, to represent the latitudinal temperature dependence. We find that there are no significant differences between results for the morning and evening terminators at any latitude and that the cloud base moves downwards as the latitude increases due to decreasing temperatures. The UH is not affected much by varying the temperature profiles; however, the haze does show some periodic differences, and is slightly thicker at the poles than at the equator. We also find that the sulphuric acid "rain" seen in previous models may be restricted to the equatorial regions of Venus, such that the particle size distribution is relatively stable at higher latitudes and at the poles.

Additional Information

© 2015 Elsevier Ltd. Received 15 March 2014; Received in revised form 8 November 2014; Accepted 27 January 2015; Available online 20 March 2015. Venus Express is a planetary mission from the European Space Agency (ESA). We wish to thank all ESA members who participated in the mission, in particular, H. Svedhem and D. Titov. We thank our collaborators at IASB-BIRA (Belgium), Latmos (France), and IKI (Russia). We thank CNES, CNRS, Roskosmos, and the Russian Academy of Science. The research program was supported by the Belgian Federal Science Policy Office and the European Space Agency (ESA, PRODEX program, contracts C 90268, 90113, and 17645). We acknowledge the support of the "Interuniversity Attraction Poles" programme financed by the Belgian government (Planet TOPERS). The research leading to these results has received funding from the European Union Seventh Framework Program (FP7/2007-2013) under grant agreement no. 606798. A. Mahieux thanks the FNRS for the position of "chargé de recherche". VeRa is partially funded by the Deutsches Zentrum für Luft- und Raumfahrt (DLR) unter Contract 50 QM 1004. The contribution of Bougher was funded in part by subcontract no. B99073JD to Southwest Research Institute.

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August 22, 2023
August 22, 2023