A numerical model of the atmosphere of Venus

Lee, C.; Lewis, S. R.; Read, P. L.

doi:10.1016/j.asr.2005.03.120

Cited by 51 publications

(69 citation statements)

References 12 publications

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“…The horizontal equatorward eddy transport of momentum at 40-80 km is responsible for maintaining the equatorial super-rotation (Lee 2006;Lee et al 2007). The model produces equatorial Kelvin and Mixed-RossbyGravity (MRG) waves spontaneously.…”

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confidence: 99%

“…In this study we investigate the likely cause of these unphysical and inaccurate thermal wind retrievals in the polar regions, using fully self-consistent simulations of Venus atmospheric circulation with a simplified general circulation model (Lee et al 2005;Lee 2006; Lee et al 2007). Likely causes are either due to a breakdown of cyclostrophic balance or the amplifications of observational errors in the assumed lower boundary condition of the cyclostrophic retrieval.…”

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confidence: 99%

“…The latter is derived from the superposition of a global-averaged reference temperature profile, obtained from Pioneer Venus probe data (Seiff et al, 1980), plus a perturbation that is function of latitude and pressure that determines the equator-to-pole thermal contrast at each altitude. This structure is chosen to produce a peak in solar heating within the altitude range of the observed cloud deck (Tomasko et al 1985;Lee 2006;Lee et al 2007). …”

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confidence: 99%

“…The SGCM used here is called the Oxford Planetary Unified (Model) System for Venus (OPUS-V), and obtains a dynamically self-consistent representation of the circulation of the Venus' atmosphere (Lee et al 2005;Lee 2006;Lee et al 2007). …”

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confidence: 99%

“…In the three upper most layers a sponge layer is included, with Rayleigh friction acting to damp horizontal eddy winds to zero (though not the zonal mean flow; Lee 2006;Lee et al 2007). …”

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confidence: 99%

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Zonal winds at high latitudes on Venus: An improved application of cyclostrophic balance to Venus Express observations

Mendonça

Read

Wilson

et al. 2012

Icarus

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Recent retrievals of zonal thermal winds obtained in a cyclostrophic regime on Venus are generally consistent with cloud tracking measurements at midlatitudes, but become unphysical in polar regions where the values obtained above the clouds are often less than or close to zero. Using a global atmospheric model, we show that the main source of errors that appear in the polar regions when retrieving the zonal thermal winds, is most likely due to uncertainties on the zonal wind intensity in the choice of the lower boundary condition.Here we suggest a new and robust method to better estimate the lower boundary condition for high latitudes, thereby improving the retrieved thermal zonal winds throughout the high latitudes middle atmosphere. This new method is applied to temperature fields derived from Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) data on board the Venus Express spacecraft. We obtain a thermal zonal wind field that is in better agreement with other, more direct methods based on either retrieving the zonal winds from cloud tracking or from direct measurements of the meridional slope of pressure surfaces.

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confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

“…In the three upper most layers a sponge layer is included, with Rayleigh friction acting to damp horizontal eddy winds to zero (though not the zonal mean flow; Lee 2006;Lee et al 2007). …”

mentioning

confidence: 99%

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Zonal winds at high latitudes on Venus: An improved application of cyclostrophic balance to Venus Express observations

Mendonça

Read

Wilson

et al. 2012

Icarus

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Effects of Polar Indirect Circulation on Superrotation and Multiple Equilibrium in Long‐Term AGCM Experiments With an Idealized Venus‐Like Forcing: Sensitivity to Horizontal Resolution and Initial Condition

Yamamoto

Takahashi

2018

JGR Planets

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A simplified model setup has been used in atmospheric general circulation models (AGCMs), to clarify the fluid dynamical process of terrestrial planets. In the present work, the research aim is to ascertain the dynamical effects of polar indirect circulation on superrotation and multiple equilibrium states in Venus‐like planets. The model setup previously used for Venus AGCM intercomparison is applied to the Model for Interdisciplinary Research On Climate AGCM, and the horizontal resolution and initial conditions are altered in the long‐term experiments. The structures of general circulation and planetary‐scale waves in the T42 (Truncation wave number 42) experiment are similar to those in the T63 experiment. In the presence of the polar indirect circulation, the superrotational flow weakens in the cloud layer and its momentum is transported toward the lower atmosphere at high latitudes. In contrast, in the T21 experiment, because the polar indirect circulation is not fully resolved, the vertical momentum transport due to the indirect circulation is ineffective in the lower atmosphere, and thus, the cloud top superrotational flow becomes greater than those in the higher‐resolution experiments. The multiple equilibrium states caused by different initial zonal flows appear in the T21 experiments, although they are not seen in the experiments of T42 and higher. Thus, the polar indirect circulation in the Gierasch‐Rossow‐Williams mechanism weakens the superrotational flow in the cloud layer and breaks the steady state multiplicity of the general circulation.

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Equatorial superrotation in Held and Suarez like flows with weak equator‐to‐pole surface temperature gradient

Polichtchouk

Cho

2016

Quart J Royal Meteoro Soc

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Equatorial superrotation under zonally-symmetric thermal forcing is investigated in a setup close to that of the classic Held and Suarez (1994) setup. In contrast to the behaviour in the classic setup, a transition to equatorial superrotation occurs when the equator-to-pole surface equilibrium entropy gradient is weakened. Two factors contribute to this transition: 1) the reduction of breaking Rossby waves from the mid-latitude that decelerate the equatorial flow and 2) the presence of barotropic instability in the equatorial region, providing stirring to accelerate the equatorial flow. In the latter, Kelvin waves excited by instability near the equator generate and maintain the superrotation. However, the superrotation is unphysically enhanced if simulations are underresolved and/or over-dissipated.

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A numerical model of the atmosphere of Venus

Cited by 51 publications

References 12 publications

Zonal winds at high latitudes on Venus: An improved application of cyclostrophic balance to Venus Express observations

Zonal winds at high latitudes on Venus: An improved application of cyclostrophic balance to Venus Express observations

Effects of Polar Indirect Circulation on Superrotation and Multiple Equilibrium in Long‐Term AGCM Experiments With an Idealized Venus‐Like Forcing: Sensitivity to Horizontal Resolution and Initial Condition

Equatorial superrotation in Held and Suarez like flows with weak equator‐to‐pole surface temperature gradient

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