Modeling the clouds on Venus: model development and improvement of a nucleation parameterization

Abstract : As both the clouds of Venus and aerosols in the Earth's stratosphere are composed of sulfuric acid droplets, we use a model [1,4] developed for stratospheric aerosols and clouds to study the clouds on Venus. The model describes key microphysical processes including a parameterization for two-component nucleation [8] of water and sulfuric acid, condensation/evaporation, and sedimentation. Coagulation and turbulent diffusion are being added in the 1-D version of the model. Since the model describes explicitly the size distribution with tens of size bins (50-500), it can handle multiple particle modes. The existing nucleation parameterization [7] has been improved to cover the very low relative humidity (RH) found in the atmosphere of Venus. We have made several modifications to improve the 2002 model [7], most notably ensuring that the two-component model behaves as predicted by the analytical studies at the one-component limit reached at extremely low RH. We have also chosen to use a self-consistent cluster distribution [9], constrained by scaling it to recent quantum chemistry calculations [3]. First tests of the model have been carried out with temperature profiles from VIRA [2] and from the LMD Venus GCM [5], and with a compilation of water vapor and sulfuric acid profiles, as in [6]. Preliminary results are evaluated against observations. [1] Jumelet et al., JGR, 2009. [2] Kliore et al., 1986. [3] Kurtén et al., BER, 2007 [4] Larsen et al., JGR, 2000. [5] Lebonnois et al. JGR, 2010. [6] McGouldrick and Toon, Icarus 191, 2007. [7] Vehkamäki et al. JGR, 2002 [9] Wilemski and Wyslouzil, J.Chem.Phys. 1995.
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Submitted on : Tuesday, November 19, 2013 - 7:59:36 PM
Last modification on : Thursday, July 25, 2019 - 4:34:10 PM

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  • HAL Id : hal-00906481, version 1

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Anni Määttänen, Slimane Bekki, Hanna Vehkamäki, Jan Julin, Franck Montmessin, et al.. Modeling the clouds on Venus: model development and improvement of a nucleation parameterization. International Venus Workshop, Jun 2013, Catania, Italy. ⟨hal-00906481⟩

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