Modifying the Creme Brulee model: Implications for the recent Equatorial Zone disturbance

Jupiters Equatorial Zone (EZ) has been undergoing a disturbance for the last several years, changing its normally white color to a reddish-brown hue. Preliminary work showed that this weather event was accompanied by a high, thick haze (Orton et al. 2021 53rd AAS Division for Planetary Sciences, Abstract 1180) but also exhibits a distinct lack of the dramatic cloud-clearing in the main cloud deck that usually accompanies such a disturbance (Antunano et al. 2018 Geophys. Res. Lett. 45, 10987-10995). As a part of the international ground-based observing campaign in support of the Juno mission, we captured optical hyperspectral image cubes of Jupiter in April 2019 in conjunction with Junos 19th perijove pass. These data were obtained with the NMSU Acousto-optic Imaging Camera (NAIC) on the Astrophysical Research Consortiums 3.5-m telescope at Apache Point Observatory in Sunspot, NM. In order to better understand the changes in the color and structure of the EZ and the differences between quiescent and disturbed periods, we conducted radiative transfer modeling with the Non-Linear Optimal Estimator for Multivariate Spectral Analysis (NEMESIS) software. Using NEMESIS and optical NAIC spectra from a range of viewing geometries, we tested several parameterizations of Jupiters uppermost cloud deck, including the Creme Brulee model and variations thereof that allowed for a thicker chromophore layer or a mixture between the chromophore layer and stratospheric haze. The relative success of these various models and their differences from models of the quiescent EZ all provide insight into how these disturbances modify Jupiters clouds and hazes. They also reveal important clues to the mechanisms responsible for the nature of this particular disturbance, the lofting of particles to create the high, thick equatorial haze, and how the chemistry responsible for Jupiters cloud colors is related to physical parameters such as altitude.