National Center for Scientific Research, France | 2020 Aug 05
New Juno results suggest that the violent thunderstorms taking place in Jupiter’s atmosphere may form ammonia-rich hail, or ‘mushballs’, that play a key role in the planet’s atmospheric dynamics. This theory, developed using data from Juno’s microwave radiometer by the Juno team, ... led by a researcher at the Laboratoire Lagrange ... The theory sheds light on some puzzling aspects of the meteorology of Jupiter and has implications for how giant planet atmospheres work in general. ...
- Cyclone observed in Jupiter’s northern hemisphere by JunoCam in July 2018. The central part covers an area of 3200 x 3800 km. White clouds of ammonia can be seen, rotating anticlockwise. Clouds rising as much as 15 km above the others (based on the shadow they cast) are visible in several places, especially in the upper central part of the cyclone. These storms are thought to contain a kind of water-ammonia hail (‘mushballs’) specific to Jupiter’s atmosphere, which drags the ammonia down into the deep atmosphere and may explain the presence of shallow lightning flashes. © NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill
In the first article, researchers from the US and the Laboratoire Lagrange suggest that when these crystals interact with gaseous ammonia, the ammonia acts as an anti-freeze, changing the ice to a liquid. ...
Measurements by Juno discovered that while ammonia is abundant near Jupiter’s equator, it is highly variable and generally depleted elsewhere to very deep pressures. ... To explain Juno’s discovery of ammonia’s deep variability across most of Jupiter, the researchers developed an atmospheric mixing model that is presented in a second article. ...
In a third article, the researchers report observations of Jovian lightning flashes by one of Juno’s cameras. The small flashes appear as bright spots on the cloud tops, with sizes proportional to their depth in Jupiter’s atmosphere. ...
'Shallow Lightning' and 'Mushballs' Reveal Ammonia to Juno Scientists
NASA | JPL-Caltech | SwRI | Juno | 2020 Aug 05
Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of 'Mushballs' ~ Tristan Guillot et al
- Journal of Geophysical Research: Planets 125(8):403 (Aug 2020) DOI: 10.1029/2020JE006403
- Journal of Geophysical Research: Planets 125(8):404 (Aug 2020) DOI: 10.1029/2020JE006404
- Nature 584(7819):55 (06 Aug 2020) DOI: 10.1038/s41586-020-2532-1