This is a past event
Interdisciplinary seminar by Xinmiao (Anna) Hu (University of Oxford).
Topic: Effect of bottom thermal forcing on Baroclinic instability in a Jupiter GCM
Note: Location is MT317 (Physics common room) not MT311 as usual.
The atmospheric circulation of Jupiter is shaped by a complex interplay between deep internal processes and cloud-level dynamics. Numerical simulations and observational analyses have suggested that Jupiter’s mid-latitude jets are strongly influenced by baroclinic instability, which is governed by the planet’s atmospheric thermal structure. Jupiter emits a substantial intrinsic heat flux originating from its deep interior. Previous modelling efforts have shown that this internal heat plays a crucial role in driving and maintaining large-scale atmospheric dynamics. However, owing to limited constraints on conditions at depth, this heat flux is typically assumed to be spatially and temporally uniform.
In this study, we challenge this conventional assumption by introducing latitudinal variations in internal heat flux into a General Circulation Model (GCM) of Jupiter’s atmosphere. We showed that latitudinal variations in interior heat flux can significantly impact the structure and behaviour of Jupiter’s mid-latitude jets in a GCM. We present a detailed analysis linking these jet modifications to changes in the atmospheric thermal structure and, consequently, to the strength and distribution of baroclinic eddy activity. In particular, we use the Lorenz energy cycle framework to diagnose how variations in deep thermal forcing influence baroclinic energy conversion and eddy-mean flow interactions. We further examine the implications for meridional transport and the water cycle within Jupiter’s weather layer.
Additionally, we present a control simulation in which the potential temperature at the model’s lower boundary is forced toward a fixed value (a deep adiabat setup). We compute the equivalent upward heat flux associated with this forcing to place it in the context of previous models that impose constant or latitudinally varying interior heat flux. This allows a direct comparison of how different representations of deep thermal forcing affect upper-atmospheric dynamics.
Finally, we discuss the broader implications of these findings for future weather-layer models of Jupiter and other gas giant planets, especially on the effect of bottom boundary conditions in representing the coupling between deep and observable atmospheric dynamics.
- Speaker
- Xinmiao (Anna) Hu
- Venue
- Meston 317