Wulff, P.P.WulffChristensen, U. R.U. R.ChristensenDietrich, W.W.DietrichWicht, J.J.Wicht2024-03-042024-03-042024https://resolver.sub.uni-goettingen.de/purl?gro-2/141903The outer areas of Jupiter and Saturn have multiple zonal winds, reaching the high latitudes, that penetrate deep into the planets' interiors, as suggested by gravity measurements. These characteristics are replicable in numerical simulations by including both a shallow stably stratified layer, below a convecting envelope, and increasing electrical conductivity. A dipolar magnetic field, assumed to be generated by a dynamo below our model, is imposed. We find that the winds' depth into the stratified layer depends on the local product of the squared magnetic field strength and electrical conductivity. The key for the drop‐off of the zonal winds is a meridional circulation which perturbs the density structure in the stable layer. In the stable region its dynamics is governed by a balance between Coriolis and electromagnetic forces. Our models suggest that a stable layer extending into weakly conducting regions could account for the observed deep zonal wind structures.Plain Language Summary Jupiter and Saturn's atmospheres display persistent east‐west zonal jets, similar to Earth. These jets, extending 2,500–3,000 km and 8,000–9,000 km into Jupiter and Saturn's interiors respectively, have been challenging to simulate. Current numerical models struggle to replicate multiple jets, spanning all latitudes and their decay at the depths inferred from gravity measurements. This study explores the hypothesis that a stably stratified layer, located at the transition to a semi‐conducting region, allows the generation of mid‐latitude zonal winds and their damping at depth. Using 3D numerical simulations, we model the outer 30% of the planets where the upper part convects and the lower part is stably stratified. We impose a dipolar magnetic field at the lower boundary and electrical conductivity increases with depth. We observe that the decay in jet amplitude in the stable region depends on the local strength of the magnetic forces. Deep within the stable region, these Lorentz forces are balanced by meridional flow, which leads to temperature perturbations and efficient zonal wind quenching.Key Points Our numerical models examine the conditions needed to form zonal winds in gas planets, complying with observed gravity and magnetic data A stable layer and magnetic forces are key for strong surface winds at high latitudes that are damped at the inferred depths The decay profile of the winds in the stable layer is controlled by the product of conductivity and squared magnetic field strengthenhttp://creativecommons.org/licenses/by/4.0/journal_article10.1029/2023JE008042