Characterization of the ovals in Jupiter's atmosphere using the first data by Juno/JIRAM instrument
Sindoni, G. ; Adriani, A. ; Mura, A. ; ...Plainaki, C. ; ...Olivieri, A.
Sep - 2017

Event Title : European Planetary Science Congress 2017, held 17-22 September, 2017 in Riga Latvia
Published in: EPSC 2017-850
Publisher: EPSC
type: Conference Proceedings

Since the first orbits, the Jovian InfraRed Auroral Mapper (JIRAM) aboard the NASA/Juno spacecraft observed several oval vortices in the Jupiter's atmosphere with the highest spatial resolution achieved so far from space-borne infrared instruments. In particular, JIRAM highlighted a line of closely spaced oval features in Jupiter's southern hemisphere, between 30°S and 45°S, as well as other persistent vortices in the northern hemisphere. The longitudinal region between 120°W and 60°W in System III coordinates covers the three ovals having higher contrast at 5 μm. Using the JIRAM's full spectral capability in the range 2.4-3 μm, which is sensitive to changes in high tropospheric clouds and in stratospheric hazes, as well as to gaseous ammonia, together with a Bayesian data inversion approach we retrieved maps of column densities and altitudes for an NH3 cloud and a photochemical haze. The deep well-mixed volume mixing ratio and the relative humidity for gaseous ammonia were also retrieved. Our results suggest different vortex activity for the studied ovals. Vertical atmospheric dynamics together with considerations about the ammonia condensation could explain our maps providing evidence of cyclonic and anticyclonic structures.

keywords :