Morphological aspects of Jupiters cyclones based on JIRAM observations and related implications
Abstract
JIRAM (the Jovian InfraRed Auroral Mapper) is an infrared camera and spectrometer on board Juno. Since 2016, it has performed several observations of the polar regions of the planet, thanks to the unique orbital design of the Juno mission. In the north polar region, Juno discovered, in 2017, the presence of an eight-cyclone structure around a single polar cyclone; in the south, a polar cyclone is surrounded by five circumpolar cyclones. The stability of these structures has been monitored for almost 5 years. Recent observations showed that the configurations of the cyclones can temporarily change: in the South the structure moved in a hexagon for a few months, before returning to its original pentagonal shape. In the north, there are significant hints that the octagonal shape may have been lost for a similar period of time. Moreover, the morphology of single cyclones are quite stable over long periods of time, with some noticeable and sudden exceptions. We find that all cyclones show a very slow, westward drift as a rigid ensemble, and, in addition, they oscillate around their rest position with similar timescales. These oscillations seem to propagate from cyclone to cyclone. Here we present the latest observation of these cyclones and we discuss the implications of their secular motion. We also integrate previous studies on the subject with dedicated velocity and vorticity maps, which show an anticyclonic vorticity field surrounding the main cyclones and acting like a stabilizer for the polar structure.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.P23A..07M