Turbulence Power Spectra in Regions Surrounding Jupiter's South Polar Cyclones From Juno/JIRAM

We present a power spectral analysis of two narrow annular regions near Jupiter's South Pole derived from data acquired by the Jovian Infrared Auroral Mapper instrument onboard NASA's Juno mission. In particular, our analysis focuses on the data set acquired by the Jovian Infrared Auroral Mapper M‐band imager (hereafter IMG‐M) that probes Jupiter's thermal emission in a spectral window centered at 4.8 μm. We analyze the power spectral densities of circular paths outside and inside of cyclones on images acquired during six Juno perijoves. The typical spatial resolution is around 55 km pixel−1. We limited our analysis to six acquisitions of the South Pole from February 2017 to May 2018. The power spectral densities both outside and inside the circumpolar ring seem to follow two different power laws. The wave numbers follow average power laws of −0.9 ± 0.2 (inside) and −1.2 ± 0.2 (outside) and of −3.2 ± 0.3 (inside) and −3.4 ± 0.2 (outside), respectively, beneath and above the transition in slope located at ~2 × 10−3 km−1 wave number. This kind of spectral behavior is typical of two‐dimensional turbulence. We interpret the 500 km length scale, corresponding to the transition in slope, as the Rossby deformation radius. It is compatible with the dimensions of a subset of eddy features visible in the regions analyzed, suggesting that a baroclinic instability may exist. If so, it means that the quasi‐geostrophic approximation is valid in this context.

[1]  O. Phillips On the dynamics of unsteady gravity waves of finite amplitude Part 1. The elementary interactions , 1960, Journal of Fluid Mechanics.

[2]  O. Phillips On the dynamics of unsteady gravity waves of finite amplitude Part 2. Local properties of a random wave field , 1961, Journal of Fluid Mechanics.

[3]  R. Kraichnan Inertial Ranges in Two‐Dimensional Turbulence , 1967 .

[4]  R. Kraichnan Inertial-range transfer in two- and three-dimensional turbulence , 1971, Journal of Fluid Mechanics.

[5]  P. Rhines Waves and turbulence on a beta-plane , 1975, Journal of Fluid Mechanics.

[6]  L. Travis Nature of the Atmospheric Dynamics on Venus from Power Spectrum Analysis of Mariner 10 Images , 1978 .

[7]  P. Gierasch,et al.  Stability of zonal flows on Jupiter , 1981 .

[8]  A. Chédin,et al.  The tropospheric gas composition of Jupiter's north equatorial belt /NH3, PH3, CH3D, GeH4, H2O/ and the Jovian D/H isotopic ratio , 1982 .

[9]  J. Holton Geophysical fluid dynamics. , 1983, Science.

[10]  A. Kolmogorov The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers , 1991, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[11]  A. Kolmogorov,et al.  The local structure of turbulence in incompressible viscous fluid for very large Reynolds numbers , 1991, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[12]  M. Maltrud,et al.  Energy and enstrophy transfer in numerical simulations of two-dimensional turbulence , 1993 .

[13]  Jupiter's Tropospheric Thermal Emission. II. Power Spectrum Analysis and Wave Search , 1996 .

[14]  C. H. Acton,et al.  Ancillary data services of NASA's Navigation and Ancillary Information Facility , 1996 .

[15]  B. Conrath,et al.  COMPARISON OF THE STRUCTURE AND DYNAMICS OF JUPITER'S GREAT RED SPOT BETWEEN THE VOYAGER 1 AND 2 ENCOUNTERS , 1996 .

[16]  A. Vasavada,et al.  Dynamics of Jupiter's Atmosphere , 1998 .

[17]  J. A. Magalhāes,et al.  The Stratification of Jupiter's Troposphere at the Galileo Probe Entry Site , 2000 .

[18]  D. Gurarie,et al.  Quasi-two-dimensional turbulence , 2000 .

[19]  J. Bendat,et al.  Random Data: Analysis and Measurement Procedures , 1987 .

[20]  R. Carlson,et al.  The Origin of Belt/Zone Contrasts in the Atmosphere of Jupiter and Their Correlation with 5-μm Opacity , 2001 .

[21]  R. Beebe Jupiter: The Planet, Satellites and Magnetosphere , 2005 .

[22]  B. Galperin,et al.  On the arrest of inverse energy cascade and the rhines scale , 2006 .

[23]  A. Sánchez-Lavega,et al.  Cloud brightness distribution and turbulence in Venus using Galileo violet images , 2007 .

[24]  S. Pérez-Hoyos,et al.  Brightness power spectral distribution and waves in Jupiter's upper cloud and hazes , 2009 .

[25]  D. S. Choi,et al.  Power spectral analysis of Jupiter's clouds and kinetic energy from Cassini , 2011, 1301.6132.

[26]  Erich L. Foster,et al.  A Finite Element Discretization of the Streamfunction Formulation of the Stationary Quasi-Geostrophic Equations of the Ocean , 2012, 1210.3630.

[27]  The vertical structure of Jupiter's equatorial zonal wind above the cloud deck, derived using mesoscale gravity waves , 2013, 1303.2022.

[28]  Christina Kluge,et al.  Data Reduction And Error Analysis For The Physical Sciences , 2016 .

[29]  Katharina Burger,et al.  Random Data Analysis And Measurement Procedures , 2016 .

[30]  C. Hansen,et al.  The first close‐up images of Jupiter's polar regions: Results from the Juno mission JunoCam instrument , 2017 .

[31]  P. Read,et al.  Forward and inverse kinetic energy cascades in Jupiter’s turbulent weather layer , 2017, Nature Physics.

[32]  G. Piccioni,et al.  JIRAM, the Jovian Infrared Auroral Mapper , 2017 .

[33]  B. Butler,et al.  Atmospheric waves and dynamics beneath Jupiter's clouds from radio wavelength observations , 2017, 1701.03484.

[34]  A. Ingersoll,et al.  Preliminary results on the composition of Jupiter's troposphere in hot spot regions from the JIRAM/Juno instrument , 2017 .

[35]  A. Sánchez-Lavega,et al.  Atmospheric Dynamics of Giants and Icy Planets , 2017 .

[36]  C. Hansen,et al.  Clusters of cyclones encircling Jupiter’s poles , 2018, Nature.

[37]  C. Hansen,et al.  First Estimate of Wind Fields in the Jupiter Polar Regions From JIRAM‐Juno Images , 2018, Journal of Geophysical Research: Planets.

[38]  A. Simon,et al.  Jupiter's Turbulent Power Spectra From Hubble Space Telescope , 2019, Journal of Geophysical Research: Planets.

[39]  J. Reinaud Three-dimensional quasi-geostrophic vortex equilibria with $m$ -fold symmetry , 2019, Journal of Fluid Mechanics.

[40]  S. Brueshaber,et al.  Dynamical regimes of giant planet polar vortices , 2019, Icarus.

[41]  G. Piccioni,et al.  Two‐Year Observations of the Jupiter Polar Regions by JIRAM on Board Juno , 2020, Journal of Geophysical Research: Planets.