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| Titel |
A comparative analysis of Simplified General Circulation Models of Venus atmosphere |
| VerfasserIn |
Sébastien Lebonnois, Curt Covey, Christopher Lee, Stephen R. Lewis, Helen Parish, Peter L. Read, Gerald Schubert, Masaru Yamamoto |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035905
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| Zusammenfassung |
| With the successful Venus Express mission and future missions planned for Venus
exploration in the near future, study of the Venus atmosphere has been rapidly expending in
the last few years. The development of General Circulation Models (GCMs) has focused on
helping researchers to understand the details of the superrotation mechanism and other
interactions within this complex atmospheric system.
Several groups that have been developing such tools have joined together within the
framework of a working group supported by the International Space Science Institute
(ISSI, Berne, Switzerland), and have started to compare how the different models
behave under the same forcing conditions. The goal of this intercomparison project is
to test how robust the response of the different numerical models is to identical
constraints.
Such a project has already been conducted recently at CalTech (Lee and Richardson, JGR
in press, 2009) using three different dynamical cores within a common model frame, and we
wanted to build upon this first study. We developed a common protocol and conducted many
simulations of Venus atmospheric circulation with five additional GCMs, using different
types of dynamical cores (spectral, finite differences or finite volumes). The baseline common
parameters include resolution, initial conditions, planetary and atmospheric parameters as
well as several physical parameterizations: thermal forcing, upper and lower boundary
conditions. In this work, thermal forcing is reduced to a simple newtonian cooling
parameterization with diurnally averaged conditions and no orbital variation of solar
forcing.
Comparison among the models shows how the different models spin up, yielding different
final states. Though all models do reach states with significantly positive superrotation, the
amplitude and shape of the zonal wind fields is highly variable between different GCMs. We
discuss the angular momentum transport mechanism, as well as the response of the different
models to variations in key parameters (resolution, boundary conditions, the form of the
temperature forcing function, ...).
Though this work is done using a simplified thermal forcing and therefore may not be
fully representative of the real Venus atmosphere, it brings some guiding elements to the
community on the degree of complexity and sensitivity of the GCMs currently developed for
the Venus atmosphere. It also illustrates interesting differences between dynamical model
cores of the type in common use in terrestrial GCMs under conditions which lead to small
residual differences becoming highly significant. |
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