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| Titel |
Three-dimensional turbulence-resolving modeling of the Venusian cloud layer and induced gravity waves |
| VerfasserIn |
Maxence Lefèvre, Aymeric Spiga, Sébastien Lebonnois |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138921
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| Publikation (Nr.) |
 EGU/EGU2017-2062.pdf |
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| Zusammenfassung |
| The impact of the cloud convective layer of the atmosphere of Venus on the global circulation
remains unclear. The recent observations of gravity waves at the top of the cloud by the Venus
Express mission provided some answers. These waves are not resolved at the scale of
global circulation models (GCM), therefore we developed an unprecedented 3D
turbulence-resolving Large-Eddy Simulations (LES) Venusian model (Lefèvre et al, 2016
JGR Planets) using the Weather Research and Forecast terrestrial model. The forcing
consists of three different heating rates : two radiative ones for solar and infrared
and one associated with the adiabatic cooling/warming of the global circulation.
The rates are extracted from the Laboratoire de Météorlogie Dynamique (LMD)
Venus GCM using two different cloud models. Thus we are able to characterize the
convection and associated gravity waves in function of latitude and local time. To
assess the impact of the global circulation on the convective layer, we used rates
from a 1D radiative-convective model. The resolved layer, taking place between
1.0 105 and 3.8 104 Pa (48-53 km), is organized as polygonal closed cells of about
10 km wide with vertical wind of several meters per second. The convection emits
gravity waves both above and below the convective layer leading to temperature
perturbations of several tenths of Kelvin with vertical wavelength between 1 and
3 km and horizontal wavelength from 1 to 10 km. The thickness of the convective
layer and the amplitudes of waves are consistent with observations, though slightly
underestimated. The global dynamics heating greatly modify the convective layer. |
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