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1. Introduction Superrotating (prograde) equatorial jets are ubiquitous in planetary atmospheres. Jupiter and Saturn exhibit equatorial superrotation, as do Venus and Titan ( Porco et al. 2003 ; Sanchez-Lavega et al. 2007 ; Schubert 1983 ; Kostiuk et al. 2001 ). Yet it has remained unclear what distinguishes atmospheres that exhibit equatorial superrotation from those that do not. For example, in an order of magnitude sense, the giant planets Jupiter, Saturn, Uranus, and Neptune have similar
1. Introduction Superrotating (prograde) equatorial jets are ubiquitous in planetary atmospheres. Jupiter and Saturn exhibit equatorial superrotation, as do Venus and Titan ( Porco et al. 2003 ; Sanchez-Lavega et al. 2007 ; Schubert 1983 ; Kostiuk et al. 2001 ). Yet it has remained unclear what distinguishes atmospheres that exhibit equatorial superrotation from those that do not. For example, in an order of magnitude sense, the giant planets Jupiter, Saturn, Uranus, and Neptune have similar
constraints be considered separately. Interestingly, decoupling of the dynamical constraints from the barrier mechanism leads to the possibility that transport barriers in PV-conserving flows may occur at locations that do not coincide with PV barriers. Rypina et al. (2007a) predicted that barriers of this type should be present in close proximity to the cores of westward zonal jets in planetary atmospheres. In this paper, we demonstrate that transport barriers of this type are present in a numerically
constraints be considered separately. Interestingly, decoupling of the dynamical constraints from the barrier mechanism leads to the possibility that transport barriers in PV-conserving flows may occur at locations that do not coincide with PV barriers. Rypina et al. (2007a) predicted that barriers of this type should be present in close proximity to the cores of westward zonal jets in planetary atmospheres. In this paper, we demonstrate that transport barriers of this type are present in a numerically
1. Introduction Zonal jets are ubiquitous features of planetary atmospheres. A common feature of the solar system’s terrestrial planetary bodies with a seasonal cycle is a strong jet in the winter hemisphere. Winter jets are observed in Earth’s stratosphere and troposphere (e.g., Schneider 2006 ; Waugh et al. 2017 ), Mars’s troposphere (e.g., Waugh et al. 2016 ), and Titan’s stratosphere (e.g., Flasar and Achterberg 2009 ). These jets inhibit transport between low and polar latitudes
1. Introduction Zonal jets are ubiquitous features of planetary atmospheres. A common feature of the solar system’s terrestrial planetary bodies with a seasonal cycle is a strong jet in the winter hemisphere. Winter jets are observed in Earth’s stratosphere and troposphere (e.g., Schneider 2006 ; Waugh et al. 2017 ), Mars’s troposphere (e.g., Waugh et al. 2016 ), and Titan’s stratosphere (e.g., Flasar and Achterberg 2009 ). These jets inhibit transport between low and polar latitudes
: Photochemistry and clouds of Jupiter, Saturn and Uranus. Recent Advances in Planetary Meteorology , Cambridge University Press, 16–68. Bjoraker , G. L. , M. H. Wong , I. de Pater , and M. Adamkovics , 2015 : Jupiter’s deep cloud structure revealed using Keck observations of spectrally resolved line shapes . Astrophys. J. , 810 , 122 , https://doi.org/10.1088/0004-637X/810/2/122 . 10.1088/0004-637X/810/2/122 Bolton , S. J. , and Coauthors , 2017 : Jupiter’s interior and deep atmosphere
: Photochemistry and clouds of Jupiter, Saturn and Uranus. Recent Advances in Planetary Meteorology , Cambridge University Press, 16–68. Bjoraker , G. L. , M. H. Wong , I. de Pater , and M. Adamkovics , 2015 : Jupiter’s deep cloud structure revealed using Keck observations of spectrally resolved line shapes . Astrophys. J. , 810 , 122 , https://doi.org/10.1088/0004-637X/810/2/122 . 10.1088/0004-637X/810/2/122 Bolton , S. J. , and Coauthors , 2017 : Jupiter’s interior and deep atmosphere
Earth-like simulations, the Jupiter model simulates a thin shell atmosphere extending from the top of the atmosphere to an artificial rigid lower surface. The mean surface pressure is 3 bar, which is used in a series of studies by Schneider and Liu ( Schneider and Liu 2009 ; Liu and Schneider 2010 , 2011 , 2015 ). The planetary parameters are set to those of Jupiter: planetary radius a = 6.986 × 10 4 km, planetary angular velocity Ω = 1.7587 × 10 −4 s −1 , and specific gas constant R = 3605
Earth-like simulations, the Jupiter model simulates a thin shell atmosphere extending from the top of the atmosphere to an artificial rigid lower surface. The mean surface pressure is 3 bar, which is used in a series of studies by Schneider and Liu ( Schneider and Liu 2009 ; Liu and Schneider 2010 , 2011 , 2015 ). The planetary parameters are set to those of Jupiter: planetary radius a = 6.986 × 10 4 km, planetary angular velocity Ω = 1.7587 × 10 −4 s −1 , and specific gas constant R = 3605
planetary atmosphere. A well-documented code of the doubling–adding method is available online and the description of the method is provided by Evans and Stephens (1991) . The doubling–adding method has not been considered for operational retrievals or data assimilation owing to its huge demand on computational resources. The method has rather been used for accurate and detailed radiative transfer calculations in the field of research and education. The advanced doubling–adding (ADA) method is a recent
planetary atmosphere. A well-documented code of the doubling–adding method is available online and the description of the method is provided by Evans and Stephens (1991) . The doubling–adding method has not been considered for operational retrievals or data assimilation owing to its huge demand on computational resources. The method has rather been used for accurate and detailed radiative transfer calculations in the field of research and education. The advanced doubling–adding (ADA) method is a recent
. But the question under discussion is whether the data analyzed with a gray, two-box, unconstrained model support the MEP hypothesis for planetary atmospheres. They evidently do not. 4. Constraints on MEP If MEP is a correct thermodynamic principle the crux of a useful application is to identify and incorporate in a calculation the constraints appropriate to the problem. The more constraints that are applied, the smaller becomes the parameter space containing the solution and, for practical
. But the question under discussion is whether the data analyzed with a gray, two-box, unconstrained model support the MEP hypothesis for planetary atmospheres. They evidently do not. 4. Constraints on MEP If MEP is a correct thermodynamic principle the crux of a useful application is to identify and incorporate in a calculation the constraints appropriate to the problem. The more constraints that are applied, the smaller becomes the parameter space containing the solution and, for practical
1. Introduction The dynamics of planetary atmospheres are sensitive to planetary parameters such as their radius a and sidereal rotation rate Ω, as well as atmospheric properties such as atmospheric composition. This is borne out by the dynamics of the solar system atmospheres. Earth’s atmospheric circulation is characterized by overturning (Hadley) cells which feature air rising near the equator and sinking in the subtropics. In the midlatitudes, prograde jets with zonal velocities of
1. Introduction The dynamics of planetary atmospheres are sensitive to planetary parameters such as their radius a and sidereal rotation rate Ω, as well as atmospheric properties such as atmospheric composition. This is borne out by the dynamics of the solar system atmospheres. Earth’s atmospheric circulation is characterized by overturning (Hadley) cells which feature air rising near the equator and sinking in the subtropics. In the midlatitudes, prograde jets with zonal velocities of
1. Introduction The banded organization of clouds and zonal winds in the atmospheres of the outer planets has long fascinated atmosphere and ocean dynamicists and planetologists, especially with regard to the stability and persistence of these patterns. This banded organization, mainly apparent in clouds thought to be of ammonia and NH 4 SH ice, is one of the most striking features of the atmosphere of Jupiter. The cloud bands are associated with multiple zonal jets of alternating sign with
1. Introduction The banded organization of clouds and zonal winds in the atmospheres of the outer planets has long fascinated atmosphere and ocean dynamicists and planetologists, especially with regard to the stability and persistence of these patterns. This banded organization, mainly apparent in clouds thought to be of ammonia and NH 4 SH ice, is one of the most striking features of the atmosphere of Jupiter. The cloud bands are associated with multiple zonal jets of alternating sign with
. Decreasing the baroclinicity of the atmosphere produces a superrotating atmosphere with a much weaker meridional circulation. All other parameters held constant, a decrease in the planetary rotation rate generally leads to an increase in the average equatorial wind speed ( Fig. 2 ). There are deviations from this behavior that occur at the lowest rotation rates, when the midlatitude westerly jets migrate toward the poles, as was already seen in simulations by Del Genio and Zhou (1996) . Fig . 2. Upper
. Decreasing the baroclinicity of the atmosphere produces a superrotating atmosphere with a much weaker meridional circulation. All other parameters held constant, a decrease in the planetary rotation rate generally leads to an increase in the average equatorial wind speed ( Fig. 2 ). There are deviations from this behavior that occur at the lowest rotation rates, when the midlatitude westerly jets migrate toward the poles, as was already seen in simulations by Del Genio and Zhou (1996) . Fig . 2. Upper
