Jupiter's Multi-Year Cycles of Temperature and Aerosol Variability From Ground-Based Mid-Infrared Imaging

We use a long-term record of ground-based mid-infrared (7.9-24.5 mu m) observations, captured between 1984 and late 2019 from 3-m and 8-m class observatories (mainly NASA's Infrared Telescope Facility, ESO's Very Large Telescope, and the Subaru Telescope), to characterize the long-term, multi-decade variability of the thermal and aerosol structure in Jupiter's atmosphere. In this study, spectral cubes assembled from images in multiple filters are inverted to provide estimations of stratospheric and tropospheric temperatures and tropospheric aerosol opacity. We find evidence of non-seasonal and quasi-seasonal variations of the stratospheric temperatures at 10 mbar, with a permanent hemispherical asymmetry at mid-latitudes, where the northern mid-latitudes are overall warmer than southern mid-latitudes. A correlation analysis between stratospheric and tropospheric temperature variations reveals a moderate anticorrelation between the 10-mbar and 330-mbar temperatures at the equator, revealing that upper-tropospheric equatorial temperatures are coupled to Jupiter's Equatorial Stratospheric Oscillation. The North and South Equatorial Belts show temporal variability in their aerosol opacity and tropospheric temperatures that are in approximate antiphase with one another, with moderate negative correlations in the North Equatorial Belt and South Equatorial Belt changes between conjugate latitudes at 10 degrees-16 degrees. This long-term anticorrelation between belts separated by similar to 15 degrees is still not understood. Finally we characterize the lag between thermal and aerosol opacity changes at a number of latitudes, finding that aerosol variations tend to lag after thermal variations by around 6 months at multiple latitudes. Jupiter's atmosphere displays a wide variety of perturbations in its temperatures, clouds and aerosols. In this study, we use a large set of ground-based observations captured in the mid-infrared between 1984 and 2019 to characterize long-term changes in the temperatures and aerosols. This long-term analysis show a number of cyclic disturbances, and allows us to distinguish between seasonal and non-seasonal changes in Jupiter's atmosphere. In particular, we observe that the northern mid-latitudes above 30 degrees are continuously warmer than their counterpart latitudes in the south at 10 mbar pressure level (the stratosphere), potentially due to differences in the polar haze in Jupiter, which extends to lower latitudes in the north compared to the south. Additionally, our study reveals for the first time that the thermal oscillation present in Jupiter's equatorial stratosphere at the 10-mbar pressure level (known as Jupiter's Equatorial Stratospheric Oscillation) is also observed to descend to higher pressures (330 mbar), meaning that it is not confined to the stratosphere. Finally, we also discuss the lag between temperature and aerosol changes at diverse latitudes to try to identify the mechanisms responsible for the different atmospheric disturbances observed on Jupiter. Ground-based multi-wavelength images are used to compute stratospheric and tropospheric temperature and tropospheric aerosol opacity mapsResults reveal that upper-tropospheric equatorial temperatures are coupled to Jupiter's Equatorial Stratospheric OscillationStratospheric temperatures at 10 mbar show a permanent hemispherical asymmetry at mid-latitudes, with northern mid-latitudes overall warmer than their counterparts