1,1,4- 1University of Oxford, Atmospheric, Oceanic & Planetary Physics, Physics, Oxford, United Kingdom of Great Britain – England, Scotland, Wales (p.read1@physics.ox.ac.uk)
- 2Dpto de Física Aplicada, Escuela de Ingeniería de Bilbao, UPV/EHU, Bilbao, Spain
- 3Department of Physics, École Normale Superieure, Saclay, France
- 4Department of Physics, University of Aberdeen, UK
Recent analyses of wind measurements obtained from tracking cloud motions in spacecraft images of Jupiter and Saturn[1,2] indicate that nonlinear scale-to-scale transfers of kinetic energy act from small to large scales over a wide range of length scales, much as anticipated for 2D or geostrophic turbulence paradigms. At the smallest resolvable scales, however, there is evidence in observations of a forward (downscale) transfer, at least at low and middle latitudes on Jupiter, much like in the Earth’s atmosphere. Moreover, the upscale transfers at the largest spatial scales are evidently dominated by spectrally non-local, highly anisotropic eddy-zonal interactions associated with the generation of intense zonal jets and equatorial super-rotation by direct eddy-zonal flow exchanges. Most analyses to date have emphasised the global mean interactions for both planets, thereby focusing on the spatially homogeneous and isotropic components of the turbulence. Here we present some new analyses of spectral energy transfers on both Jupiter and Saturn that resolve variations in latitude[cf 3], thereby shedding new light on non-homogeneous aspects of jovian turbulent interactions. The results indicate significant variability and inhomogeneity between different locations, with a clear distinction between the tropics, the extratropical middle latitudes and the polar regions. We discuss these in light of other observations and models of gas giant circulation and related laboratory experimental analogues.
[1] Antu˜nano, A., del Río-Gaztelurrutia, T., Sánchez-Lavega, A., & Hueso, R. (2015) Dynamics of Saturn’s polar regions. J. Geophys. Res.: Planets, 120 , 155–176. doi:10.1002/2014JE004709
[2] Read, P. L., Antu˜nano, A., Cabanes, S., Colyer, G., del Río-Gaztelurrutia, T., Sánchez-Lavega, A. (2022). Energy exchanges in Saturn’s polar regions from
Cassini observations: Eddy-zonal flow interactions. J. Geophys. Res., 127 , e2021JE006973. https://doi.org/10.1029/2021JE006973
[3] Chemke, R., & Kaspi, Y. (2015). The latitudinal dependence of atmospheric jet scales and macroturbulent energy cascades. J. Atmos. Sci., 72 , 3891–3907. doi: 10.1175/JAS-D-15-0007.1
How to cite: Read, P. L., Antunano, A., Bobas, H., Colyer, G., Ding, S., del Río Gaztelurrutia, T., Sanchez-Lavega, A., and Young, R.: Characterising turbulent cascades and zonal jet formation processes from observations of cloud level winds on Jupiter and Saturn, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-1019, https://doi.org/10.5194/epsc-dps2025-1019, 2025.
