Simulations of Superrotation on Slowly Rotating Planets: Sensitivity to Rotation and Initial Condition

Genio, Anthony D. Del; Zhou, Wei

doi:10.1006/icar.1996.0054

Cited by 82 publications

(70 citation statements)

References 2 publications

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“…Therefore, we use zonally uniform solar heating and Newtonian cooling for the reference temperature. Since our research is started from Matsuda (1980Matsuda ( , 1982 in which he extended the Gierasch mechanism based on the meridional heating difference, we adopt only meridional heating as done by many researchers (Del Genio et al (1993, 1996; Takahashi (2003a, 2003b); Hollingthworth et al (2007)). …”

Section: Modelmentioning

confidence: 99%

“…Del Genio et al (1993) andZhou (1996) reproduced super-rotation using AGCM for the earth by merely adopting the Venusian rotating rate and retaining other Earth parameters. Yamamoto and Takahashi (2003a (hereinafter, YT), 2003b) reproduced super-rotation by Venus-like AGCM that incorporates the Venus rotation rate, high surface pressure, high surface temperature, and zonally uniform solar heating; their results support the Gierasch mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Multiple Equilibrium States Appearing in a Venus-Like Atmospheric General Circulation Model

Kido

Wakata

2008

Journal of the Meteorological Society of Japan

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969 IntroductionVenus has a thick CO 2 atmosphere with surface pressure of 9.2 × 10 4 hPa. The surface temperature is about 730 K because of the greenhouse effect imparted by thick CO 2 gas. Sulfuric acid clouds blanket the entire planet at about 47−70 km. An important characteristic of Venus is its very slow rotation: its rotation period is 243 earth days. One Venus Solar day is 117 days considering both daily rotation and revolution. It might therefore be speculated that convection between dayside and nightside dominates the atmospheric circulation, and that the convection pattern moves slowly together with slowly migrating subsolar and antisolar points. However, such a convection has not been observed, and observations have confirmed that fast zonal winds, called super-rotation or four-day circulation, are predominant. The Venusian cloud pattern rotates in the same direction as the rotation of the solid Venus with about four days around Venus along the equator. The zonal wind speed increases with height; its velocity is about 100 m s −1 at the cloud top level (about 70 km). The wind is 60 times faster than the solid planet. The reason why dayside-nightside circulation does not appear but super-rotation (four-day circulation) is dominant remains still unclear. Furthermore, the mechanism producing and maintaining such a fast zonal wind Japan, Vol. 86, No. 6, pp. 969−979, 2008 Journal of the Meteorological Society of AbstractWe investigated the existence of multiple equilibrium states in the Venusian atmospheric general circulation suggested by Matsuda (1980Matsuda ( , 1982 using a Venus-like atmospheric general circulation model. We ran the model from two initial conditions: a state with large zonal wind increasing with height and a motionless state. For the large zonal wind initial state, a strong zonal wind with weak meridional circulation, i.e., super-rotation, appears. However for the motionless initial condition, slow zonal wind with strong meridional circulation relative to the farmer state appears. Each circulation reached a quasi-steady state. These results have the same features suggested by Matsuda. The presence of multiple equilibrium states was sensitive to the horizontal eddy viscosity parameter. For the strong zonal wind state, the acceleration of the zonal mean zonal wind results from the horizontal EP flux divergence from the wavenumber one component on the equator, which is mainly maintained by the Gierasch mechanism (1975). The presence of multiple equilibrium states suggests that an alternative slow zonal wind state could appear in the Venusian atmosphere if an appropriate initial condition or drastic fluctuation is assigned.

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Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multiple Equilibrium States Appearing in a Venus-Like Atmospheric General Circulation Model

Kido

Wakata

2008

Journal of the Meteorological Society of Japan

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“…Previous IR heterodyne measurements of Titan wind were made using NASA's 3-meter Infrared Telescope Facility (IRTF) in 1993, 1995, and 1996near equinox [Kostiuk et al, 2001 O 2 laser local oscillator stabilized to drift 1 MHz/hr ($10 m/s/hr). Measurements were made by alternating 5 min scans on each limb (Figure 1) to minimize systematic velocity drifts.…”

Section: Observationsmentioning

confidence: 99%

“…[2] The magnitude, direction, and global and vertical distribution of Titan's winds and temperature remain important parameters for understanding the atmospheric dynamics and meteorology of slowly rotating bodies [del Genio and Zhou, 1996;Hourdin et al, 1995] and for interpretation of data retrieved from Cassini and Huygens, particularly from the Huygens Doppler Wind Experiment [Bird et al, 2002].…”

Section: Introductionmentioning

confidence: 99%

Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion

Kostiuk

Livengood

Hewagama

et al. 2005

Geophysical Research Letters

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“…Atmospheric general circulation models for Venus-like slowly rotating planets seem to favor this process as the mechanism of maintaining the super-rotation (Del Genio and Zhou, 1996;Takahashi, 2003, 2006;Lee et al, 2007;Kido and Wakata, 2008). However, these models assume either an unrealistically high solar heating rate in the deep atmosphere or an unrealistically large equator-to-pole surface temperature gradient so that a strong Hadley circulation can exist in the deep atmosphere.…”

Section: Super-rotationmentioning

confidence: 99%

Overview of Venus orbiter, Akatsuki

et al. 2011

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The Akatsuki spacecraft of Japan was launched on May 21, 2010. The spacecraft planned to enter a Venusencircling near-equatorial orbit in December 7, 2010; however, the Venus orbit insertion maneuver has failed, and at present the spacecraft is orbiting the Sun. There is a possibility of conducting an orbit insertion maneuver again several years later. The main goal of the mission is to understand the Venusian atmospheric dynamics and cloud physics, with the explorations of the ground surface and the interplanetary dust also being the themes. The angular motion of the spacecraft is roughly synchronized with the zonal flow near the cloud base for roughly 20 hours centered at the apoapsis. Seen from this portion of the orbit, cloud features below the spacecraft continue to be observed over 20 hours, and thus the precise determination of atmospheric motions is possible. The onboard science instruments sense multiple height levels of the atmosphere to model the three-dimensional structure and dynamics. The lower clouds, the lower atmosphere and the surface are imaged by utilizing nearinfrared windows. The cloud top structure is mapped by using scattered ultraviolet radiation and thermal infrared radiation. Lightning discharge is searched for by high speed sampling of lightning flashes. Night airglow is observed at visible wavelengths. Radio occultation complements the imaging observations principally by determining the vertical temperature structure.

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Simulations of Superrotation on Slowly Rotating Planets: Sensitivity to Rotation and Initial Condition

Cited by 82 publications

References 2 publications

Multiple Equilibrium States Appearing in a Venus-Like Atmospheric General Circulation Model

Multiple Equilibrium States Appearing in a Venus-Like Atmospheric General Circulation Model

Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion

Overview of Venus orbiter, Akatsuki

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