Implications of a Stable Layer on the Vertical Structure of Jet Streams on Jupiter

Abstract

The vertical structure of Jupiter's jet streams remains a critical open question for understanding the planet's atmospheric dynamics and interior. Traditional models often assume an adiabatic density profile, yet recent observations and theory suggest the presence of stable layers, which could significantly alter both the density structure and gravitational signature. We investigate the implications of non-adiabatic stable layers for Jupiter's gravity field, focusing on how density anomalies from such layers interact with the inferred vertical structure of zonal winds. We construct temperature-pressure profiles including subadiabatic stable layers to derive density profiles consistent with the latest equation of state. The resulting gravitational harmonics are computed, incorporating both static density and wind structure via thermal wind balance, and compared with Juno measurements. By varying the wind decay characteristics, we assess how stable layers constrain the depth and structure of the deep jets. Our results show that shallow, extensive stable layers substantially modify the background density, requiring more rapid decay of zonal winds to satisfy observed gravitational constraints. Introducing stable layers also broadens the range of physically plausible wind solutions, inadicating that the vertical structure of the jets is less constrained than suggested by purely adiabatic models. We conclude that stable layers are a critical, yet often overlooked, component in modeling Jupiter's interior and dynamics. This study highlights a strong degeneracy between the thermodynamic density structure and the vertical wind profile, implying that the jet stream structure cannot be uniquely determined without independent constraints on the planet's internal stability.