Strong zonal winds from thermal convection in a rotating spherical shell

Aurnou, J. M.; Olson, Peter

doi:10.1029/2000gl012474

Cited by 104 publications

(112 citation statements)

References 16 publications

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…Previous 3D convection models adopted relatively thick shells with inner/outer radius ratios typically less than ~0.7, and generally produced only a few very broad jets (Aurnou and Olson 2001;Christensen 2001Christensen , 2002. Although these early studies always produced a superrotating equatorial jet, a positive feature, there was a discouraging lack of resemblence between the simulated jet profiles and those observed on Jupiter and Saturn.…”

Section: Models For Jet Pumpingmentioning

confidence: 80%

“…The superrotating equatorial jet in the 3D Boussinesq simulations of Aurnou and Olson (2001), Christensen (2001, Heimpel et al (2005), and Heimpel and Aurnou (2007) results from the interaction of columnar convective rolls with the curving spherical planetary surface (Busse 2002;Vasavada and Showman 2005). This mechanism, which can be viewed as a ``topographic'' β effect, requires convective rolls that act as coherent Taylor columns (i.e., the convective rolls must remain coherent along their entire length from the northern to the southern boundary).…”

Section: Models For Jet Pumpingmentioning

confidence: 99%

See 1 more Smart Citation

Saturn Atmospheric Structure and Dynamics

Genio

Achterberg

Baines

et al. 2009

Saturn From Cassini-Huygens

View full text Add to dashboard Cite

Section: Models For Jet Pumpingmentioning

confidence: 80%

Section: Models For Jet Pumpingmentioning

confidence: 99%

Saturn Atmospheric Structure and Dynamics

Genio

Achterberg

Baines

et al. 2009

Saturn From Cassini-Huygens

View full text Add to dashboard Cite

“…With the advance of computational abilities numerical 3D models (Sun et al, 1993;Aurnou and Olson, 2001;Christensen, 2002) solving the full Navier-Stokes equations subject to the Boussinesq approximation have demonstrated that in a rapidly rotating system a broad eastward ow can develop at the equator. This ow has been referred to result from the so-called Busse columns, though none of these studies actually demonstrated such columns explicitly.…”

Section: Deep Modelsmentioning

confidence: 99%

“…Previous attempts to model this system fall into two general categories: convection models with deep geometry that are limited to Boussinesq dynamics (e.g. Zhang and Schubert, 1997;Aurnou and Olson, 2001;Christensen, 2002;Heimpel et al, 2005), or spherical shell atmospheric type models which lack or parametrize the interior convection (e.g. Lee, 2004;Lian et al, 2006).…”

Section: Model Overviewmentioning

confidence: 99%

Turbulent convection in an anelastic rotating sphere : a model for the circulation on the giant planets

Kaspi¹

2008

View full text Add to dashboard Cite

This thesis studies the dynamics of a rotating compressible gas sphere, driven by internal convection, as a model for the dynamics on the giant planets. We develop a new general circulation model for the Jovian atmosphere, based on the MITgcm dynamical core augmenting the nonhydrostatic model. The grid extends deep into the planet's interior allowing the model to compute the dynamics of a whole sphere of gas rather than a spherical shell (including the strong variations in gravity and the equation of state). Dierent from most previous 3D convection models, this model is anelastic rather than Boussinesq and thereby incorporates the full density variation of the planet.We show that the density gradients caused by convection drive the system away from an isentropic and therefore barotropic state as previously assumed, leading to signicant baroclinic shear. This shear is concentrated mainly in the upper levels and associated with baroclinic compressibility eects. The interior ow organizes in large cyclonically rotating columnar eddies parallel to the rotation axis, which drive upgradient angular momentum eddy uxes, generating the observed equatorial superrotation. Heat uxes align with the axis of rotation, contributing to the observed at meridional emission. We show the transition from weak convection cases with symmetric spiraling columnar modes similar to those found in previous analytic linear theory, to more turbulent cases which exhibit similar, though less regular and solely cyclonic, convection columns which manifest on the surface in the form of waves embedded within the superrotation. We develop a mechanical understanding of this system and scaling laws by studying simpler congurations and the dependence on physical properties such as the rotation period, bottom boundary location and forcing structure.These columnar cyclonic structures propagate eastward, driven by dynamics similar to that of a Rossby wave except that the restoring planetary vorticity gradient 3 is in the opposite direction, due to the spherical geometry in the interior. We further study these interior dynamics using a simplied barotropic annulus model, which shows that the planetary vorticity radial variation causes the eddy angular momentum ux divergence, which drives the superrotating equatorial ow. In addition we study the interaction of the interior dynamics with a stable exterior weather layer, using a quasigeostrophic two layer channel model on a beta plane, where the columnar interior is therefore represented by a negative beta eect. We nd that baroclinic instability of even a weak shear can drive strong, stable multiple zonal jets. For this model we nd an analytic nonlinear solution, truncated to one growing mode, that exhibits a multiple jet meridional structure, driven by the nonlinear interaction between the eddies. Finally, given the density eld from our 3D convection model we derive the high order gravitational spectra of Jupiter, which is a measurable quantity for the upcoming JUNO mission to Jupiter. Glenn Flierl, my...

show abstract

“…How convection in rotating spherical systems generates mean zonal flows has been studied for a very long time (see, for example, Busse 1970;Gilman & Glatzmaier 1981;Zhang 1992;Miesch et al 2000;Aurnou & Olson 2001;Christensen 2001;Jones et al 2003;Chan et al 2006;Heimpel & Aurnou 2007). In numerical simulations of rotating spherical convection, Grote & Busse (2001) (see also Aurnou & Olson 2001) noted that the differential rotation tends to shear off the convection columns and results in a temporal intermittency. Recent simulations of convection in a relatively thin spherical shell (Heimpel et al 2005;Heimpel & Aurnou 2007) show strong prograde equatorial jets outside the tangent cylinder while multiple jets form in the northern and southern hemispheres inside the tangent cylinder, which are very similar to those observed in Jupiter and Saturn.…”

Section: Introduction Recent Observations From the Hubble Space Telesmentioning

confidence: 99%

On the Saturation and Temporal Variation of Mean Zonal Flows: An Implication for Equatorial Jets on Giant Planets

Liao

Feng

Zhang

2007

ApJ

View full text Add to dashboard Cite

Saturation and temporal variation of the mean zonal flow in rapidly rotating quasi-geostrophic spherical systems are investigated. Convective instabilities generate highly coherent small-scale eddies that feed energy into the mean flow via the inverse cascade mechanism. We show that this inverse cascade causes a continual piling up of energy in the mean flow, which in turn strongly stabilizes the system and hence dramatically reduces the amplitude of the eddies, leading to the reduction and saturation of the mean flow. This implies that the fast equatorial zonal jets on giant planets may be unsteady.

show abstract

Strong zonal winds from thermal convection in a rotating spherical shell

Cited by 104 publications

References 16 publications

Saturn Atmospheric Structure and Dynamics

Saturn Atmospheric Structure and Dynamics

Turbulent convection in an anelastic rotating sphere : a model for the circulation on the giant planets

On the Saturation and Temporal Variation of Mean Zonal Flows: An Implication for Equatorial Jets on Giant Planets

Contact Info

Product

Resources

About