A full-atmosphere model of Jupiter

Abstract

This paper presents a combined 1D photochemical–thermochemical kinetics model of Jupiter’s deeper atmosphere, troposphere and stratosphere. The model covers atmospheric pressure range from $1.1\times 10^3$ bar to $7.4\times 10^{-11}$ bar and is the first model that incorporates sulfur chemistry when spanning an atmospheric region of this extent. This model incorporates a new version of the STAND reaction network with updated NH₄SH chemistry, and updated Antoine equation parameters for NH₄SH and H₂S. Validation against current models of Jupiter’s atmosphere as well as recent observational data shows that our model successfully describes Jupiter’s main observed chemical features. Since one of the focuses of the model is the chemistry on nitrogen, it correctly predicts the formation of a mixed NH₃-NH₄SH cloud layer between 0.1 and 1 bar. It also describes the chemistry of HCN throughout the atmosphere and discovers a region in the stratosphere between $1\times 10^{-6}$ and $6.76\times 10^{-8}$ bar, where HCN forms through radical chemistry with maximum mixing ratio 33 ppb at $2.94\times 10^{-7}$ bar – a prediction testable by observations. At the same time, our model predicts a quenched N₂ mixing ratio 490 ppm up to 10⁻⁶ bar. The model therefore successfully bridges the gap between existing models of separate regions of Jupiter’s atmosphere and makes new testable predictions of several chemical species.