Dynamical regimes of giant planet polar vortices

Brueshaber, Shawn; Sayanagi, Kunio M.; Dowling, T. E.

doi:10.1016/j.icarus.2019.02.001

Cited by 41 publications

(60 citation statements)

References 60 publications

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“…This study first demonstrated that the vortex features of the flow, i. e. the appearance (or not) of a single vortex centered at the poles, is controlled by the ratio of two characteristic sizes, namely, that of the small vortices and the planetary radius. The recent study by Brueshaber et al (2019) provides further support for the mechanism which distinguishes the specific characteristics of polar dynamics occurring in Jupiter (a ring of cyclones surrounding the poles) and Saturn (single and strong cyclone) studied in O' Neill et al (2015Neill et al ( , 2016. The key parameter which controls the transition between the latter scenarios is the Burger number, defined as the ratio between the Rossby deformation radius and the planetary radius (Brueshaber et al 2019).…”

Section: Introductionmentioning

confidence: 73%

“…The recent study by Brueshaber et al (2019) provides further support for the mechanism which distinguishes the specific characteristics of polar dynamics occurring in Jupiter (a ring of cyclones surrounding the poles) and Saturn (single and strong cyclone) studied in O' Neill et al (2015Neill et al ( , 2016. The key parameter which controls the transition between the latter scenarios is the Burger number, defined as the ratio between the Rossby deformation radius and the planetary radius (Brueshaber et al 2019). As the Burger number is decreased a transition from Saturn-like to Jupiter-like polar cyclones is observed.…”

Section: Introductionmentioning

confidence: 73%

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Deep model simulation of polar vortices in gas giant atmospheres

García

Chambers

Watts

2020

Monthly Notices of the Royal Astronomical Society

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The Cassini and Juno probes have revealed large coherent cyclonic vortices in the polar regions of Saturn and Jupiter, a dramatic contrast from the east-west banded jet structure seen at lower latitudes. Debate has centered on whether the jets are shallow, or extend to greater depths in the planetary envelope. Recent experiments and observations have demonstrated the relevance of deep convection models to a successful explanation of jet structure, and cyclonic coherent vortices away from the polar regions have been simulated recently including an additional stratified shallow layer. Here we present new convective models able to produce long-lived polar vortices. Using simulation parameters relevant for giant planet atmospheres we find flow regimes of geostrophic turbulence (GT) in agreement with rotating convection theory. The formation of large scale coherent structures occurs via three-dimensional upscale energy transfers. Our simulations generate polar characteristics qualitatively similar to those seen by Juno and Cassini: they match the structure of cyclonic vortices seen on Jupiter; or can account for the existence of a strong polar vortex extending downwards to lower latitudes with a marked spiral morphology, and the hexagonal pattern seen on Saturn. Our findings indicate that these vortices can be generated deep in the planetary interior. A transition differentiating these two polar flows regimes is described, interpreted in terms of force balances and compared with shallow atmospheric models characterising polar vortex dynamics in giant planets. In addition, heat transport properties are investigated, confirming recent scaling laws obtained with reduced models of GT.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 73%

Deep model simulation of polar vortices in gas giant atmospheres

García

Chambers

Watts

2020

Monthly Notices of the Royal Astronomical Society

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“…Likewise, retrieved horizontal wind fields only apply to a limited altitude range compared to the full vertical extent of the vortex. Subject to these types of limitations, vortex models constrained by imaging and wind field data have been extensively used to estimate atmospheric static stability on Jupiter, with many finding a deformation radius of about 2,000 km (e.g., Brueshaber & Sayanagi, 2021; Brueshaber et al., 2019; Cho et al., 2001; Shetty & Marcus, 2010).…”

Section: Discussionmentioning

confidence: 99%

Evolution of the Horizontal Winds in Jupiter's Great Red Spot From One Jovian Year of HST/WFC3 Maps

Wong

Marcus

Simon-Miller

et al. 2021

Geophysical Research Letters

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The Great Red Spot is an enduring large anticyclone in Jupiter's atmosphere, situated in the South Tropical Zone (Figure 1). Anticyclonic flow in this zone is perturbed over the northern edge of the GRS so that it locally protrudes into the typically dark and reddish South Equatorial Belt (SEB) to the north. The SEB features dramatic global-scale changes in coloration, cloud properties, and convective activity (e.g., Fletcher et al., 2011Fletcher et al., , 2017Rogers, 1995;Sánchez-Lavega & Gómez, 1996), but the most notable change in the GRS itself is more monotonic in nature: a continuous decrease in size over more than 100 years of accurate observations (Simon et al., 2018).The size and longevity of the GRS make it unique among outer solar system vortices, yet it also serves as an archetype of a class of "pancake vortices"-anticyclones embedded in stably stratified fluids-also including vortices like the dark spots on Neptune and salt lens eddies in the Earth's oceans (e.g., Dowling, 1995;Hassanzadeh et al., 2012;Yim et al., 2016). Pancake vortices have a thickness much smaller than their horizontal dimensions, like the GRS whose horizontal scale is some 50 times greater than vertical scale, according to theoretical arguments based on laboratory experiments and Jovian vortex velocity fields (Lemasquerier et al., 2020). Terrestrial ocean eddies transport heat meridionally by both stirring (turbulent) and trapping (bulk transport) mechanisms (Sun et al., 2018). Trapping is limited on Jupiter because major vortices are bounded by jets that limit meridional migration, although trapping could be significant on Saturn, where poleward migration of the anticyclone created by the 2010 Great White Storm was observed

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“…So far, most vortex formation models consider only the thin outer weather layer, with several using the shallow-water equations with a prescribed forcing in the form of moist convection or solar heating (18,19). These studies have successfully modeled several properties of the vortices, for example, the bias toward anticyclones (20,21) and polar vortex formation (22,23). However, it is also well known that coherent vortices can spontaneously form in three-dimensional (3D) fluid turbulence if rotational effects are substantial [e.g., see (24)].…”

Section: Introductionmentioning

confidence: 99%

Deep convection–driven vortex formation on Jupiter and Saturn

2020

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The surfaces of Jupiter and Saturn have magnificent vortical storms that help shape the dynamic nature of their atmospheres. Land- and space-based observational campaigns have established several properties of these vortices, with some being similar between the two planets, while others are different. Shallow-water hydrodynamics, where the vortices are treated as shallow weather-layer phenomenon, is commonly evoked for explaining their formation and properties. Here, we report novel formation mechanisms for vortices where the primary driving mechanism is the deep planetary convection occurring in these planets. Using three-dimensional simulations of turbulent convection in rotating spherical shells, we propose two ideas: (i) Rotating turbulent convection generates deep axially aligned cyclones and anticyclones; (ii) a deep planetary dynamo acts to promote additional anticyclones, some as large as Jupiter’s Great Red Spot, in an overlying atmospheric layer. We use these ideas to interpret several observational properties of vortices on Jupiter and Saturn.

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Dynamical regimes of giant planet polar vortices

Cited by 41 publications

References 60 publications

Deep model simulation of polar vortices in gas giant atmospheres

Deep model simulation of polar vortices in gas giant atmospheres

Evolution of the Horizontal Winds in Jupiter's Great Red Spot From One Jovian Year of HST/WFC3 Maps

Deep convection–driven vortex formation on Jupiter and Saturn

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