Lee, Christopher and Lewis, Stephen R. and Read, Peter L. (2010) A bulk cloud parameterization in a Venus General Circulation Model. Icarus, 206 (2). pp. 662-668. ISSN 0019-1035 http://resolver.caltech.edu/CaltechAUTHORS:20100412-090026046
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A condensing cloud parameterization is included in a super-rotating Venus General Circulation Model. A parameterization including condensation, evaporation and sedimentation of mono-modal sulfuric acid cloud particles is described. Saturation vapor pressure of sulfuric acid vapor is used to determine cloud formation through instantaneous condensation and destruction through evaporation, while pressure dependent viscosity of a carbon dioxide atmosphere is used to determine sedimentation rates assuming particles fall at their terminal Stokes velocity. Modifications are described to account for the large range of the Reynolds number seen in the Venus atmosphere. Two GCM experiments initialized with 10 ppm-equivalent of sulfuric acid are integrated for 30 Earth years and the results are discussed with reference to “Y” shaped cloud structures observed on Venus. The GCM is able to produce an analog of the “Y” shaped cloud structure through dynamical processes alone, with contributions from the mean westward wind, the equatorial Kelvin wave, and the mid-latitude/polar Mixed Rossby/Gravity waves. The cloud top height in the GCM decreases from equator to pole and latitudinal gradients of cloud top height are comparable to those observed by Pioneer Venus and Venus Express, and those produced in more complex microphysical models of the sulfur cycle on Venus. Differences between the modeled cloud structures and observations are described and dynamical explanations are suggested for the most prominent differences.
|Additional Information:||© 2009 Elsevier Inc. Received 9 July 2009; revised 9 September 2009; accepted 28 September 2009. Available online 13 October 2009. This work was funded by a PPARC studentship (C. Lee). The authors thank the UK Meteorological Office for the use of the Had- AM3 climate model in this work and Henning Böttger for the cloud parameterization upon which the Venus cloud model used in this work is based. We thank the two anonymous reviewers for their useful comments and corrections.|
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|Deposited By:||Tony Diaz|
|Deposited On:||28 Apr 2010 19:37|
|Last Modified:||26 Dec 2012 11:57|
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