Superrotation and Jet Migration in Simulations of Giant Planet Atmospheres
Abstract
The mean zonal flow on both Jupiter and Saturn consists of an intricate pattern of jets moving prograde or retrograde compared to the bulk planetary rotation. The strongest jet straddles the equator and is prograde, or superrotating. It is flanked by multiple retrograde/prograde pairs of weaker jets at high latitudes. Two candidate drivers of these jets are "shallow" quasi-two dimensional turbulence in the outermost stably stratified weather layer (WL) and "deep" buoyantly-driven Busse columns in the underlying convective zone (CZ). To study the respective roles of the WL and CZ, we implement two rotating, three-dimensional, anelastic convection simulations of a giant planet. In one case, the CZ is isolated, whereas in the other case, the upflows overshoot into a stably stratified near-surface layer, driving turbulence there. We regard this layer as a simplified WL, although we include the effects of stable stratification only, neglecting solar irradiation. In each case, we find that homogenization of an appropriately defined potential vorticity initially creates multiple jets at high latitudes, whereas Busse columns in the CZ drive equatorial superrotation. The presence of a simplified WL significantly alters the thermal wind balance, resulting in large deviations of the contours of the zonal flow from alignment with the rotation axis. Finally, the weaker high-latitude jets slowly migrate poleward and/or merge on a very long time scale (O(10) diffusion time scales or thousands of eddy turnover times).
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BibTeX
@misc{matilsky2026superrotation,
title = {{Superrotation and Jet Migration in Simulations of Giant Planet Atmospheres}},
author = {Loren Matilsky and Geoffrey Vallis and Matthew Browning and Nicholas Brummell},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.23307},
eprint = {2605.23307},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.23307},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Superrotation and Jet Migration in Simulations of Giant Planet Atmospheres
AU - Loren Matilsky
AU - Geoffrey Vallis
AU - Matthew Browning
AU - Nicholas Brummell
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2605.23307
UR - https://arxiv.org/abs/2605.23307
AB - The mean zonal flow on both Jupiter and Saturn consists of an intricate pattern of jets moving prograde or retrograde compared to the bulk planetary rotation. The strongest jet straddles the equator and is prograde, or superrotating. It is flanked by multiple retrograde/prograde pairs of weaker jets at high latitudes. Two candidate drivers of these jets are "shallow" quasi-two dimensional turbulence in the outermost stably stratified weather layer (WL) and "deep" buoyantly-driven Busse columns in the underlying convective zone (CZ). To study the respective roles of the WL and CZ, we implement two rotating, three-dimensional, anelastic convection simulations of a giant planet. In one case, the CZ is isolated, whereas in the other case, the upflows overshoot into a stably stratified near-surface layer, driving turbulence there. We regard this layer as a simplified WL, although we include the effects of stable stratification only, neglecting solar irradiation. In each case, we find that homogenization of an appropriately defined potential vorticity initially creates multiple jets at high latitudes, whereas Busse columns in the CZ drive equatorial superrotation. The presence of a simplified WL significantly alters the thermal wind balance, resulting in large deviations of the contours of the zonal flow from alignment with the rotation axis. Finally, the weaker high-latitude jets slowly migrate poleward and/or merge on a very long time scale (O(10) diffusion time scales or thousands of eddy turnover times).
ER -