Hydrodynamical and Thermochemical Modeling of Jupiter's Atmosphere - Constraining the Vertical Mass Transport

Gas giant planets are hypothesized to have two dominant pathways of formation, namely, the core accretion model and the gravitational instability model. The formation pathways primarily differ in the time and rate of accretion for the planet, with the resulting bulk composition strongly coupled to the dominant mode of accretion. Thus, characterizing the atmospheric dynamics and underlying chemistry is a means to probe the formation pathways and inform our understanding of processes that were relevant during early Solar System evolution. In Jupiter's case, the abundance of oxygen, in the form of water, functions as an important tracer for delivery of volatiles to the planet during accretion. Recent measurements of the equatorial water abundance along with other trace chemical species from the Juno spacecraft necessitate an analysis of the interplay between the disequilibrium chemistry and deep atmospheric dynamics.

We use the "Simulating Non-hydrostatic Atmosphere on Planets" (SNAP) code to tie the microphysics and hydrodynamics of Jupiter's troposphere to the well-established chemical timescale approach. This approach provides a robust approximation for chemical production/loss without needing the full intricacy of thermochemical reaction networks. We use the disequilibrium gases CO, GeH4, PH3, and AsH3 as quasi-passive Lagrangian tracers and explore the parameterization of Jupiter's atmosphere. The coupling between the chemical timescales and the microphysics provides novel constraints on the Jovian deep water abundance. As CO and GeH4 are particularly sensitive to the water enrichment factor, and GeH4 is closely tied to the vertical eddy diffusion coefficient, this formulation allows for the vertical and horizontal diffusion coefficients to be estimated directly from chemical disequilibrium, as a function of the internal heat flux and water enrichment factor. Our approach informs the bulk composition of the planet, and directly constraints the volatile delivery mechanisms that are relevant to Jupiter's formation.