EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Properties of H3+ and CH4 at mid and equatorial latitudes in the Jovian atmosphere, observed with JIRAM on Juno

Alessandra Migliorini1, Bianca M. Dinelli2, Marialuisa Moriconi3, Francesca Altieri1, Chiara Castagnoli2,4, Alessandro Mura1, Alberto Adriani1, Roberto Sordini1, Sushil Atreya5, Federico Tosi1, Scott Bolton6, Giuseppe Piccioni1, Davide Grassi1, Alessandro Moirano1, Raffaella Noschese1, Andrea Cicchetti1, Giuseppe Sindoni7, Christina Plainaki7, and Angelo Olivieri7
Alessandra Migliorini et al.
  • 1INAF-Istituto di Astrofisica e Planetologia Spaziali, Roma, Italy
  • 2CNR-Istituto di Scienze dell’Atmosfera e del Clima, Bologna, Italy
  • 3CNR-Istituto di Scienze dell’Atmosfera e del Clima, Roma, Italy
  • 4DIFA, Università di Bologna, Bologna, Italy
  • 5Planetary Science Laboratory, University of Michigan, Ann Arbor, Michigan, USA
  • 6Southwest Research Institute, San Antonio, Texas, USA
  • 7Agenzia Spaziale Italiana, Roma, Italy

The NASA Juno spacecraft is studying Jupiter’s atmosphere in depth since August 2016. The Jupiter Infrared Auroral Mapper (JIRAM) experiment (Adriani et al. 2014), one of the scientific instruments on board Juno, is composed of two broad-band imagers and an infrared spectrometer, dedicated to the observation of the auroral and chemical composition of the Jupiter’s atmosphere. Images and spectral observations in limb view geometry have been acquired since orbit 17 (December 2018) onwards, providing a wealth of details of the atmosphere at mid to equatorial latitudes, with a spatial resolution of the order of hundreds of meters per pixel. CH4 and H3+ emissions around the 3-μm region show two well separated layers at 200 km and at about 500-600 km above the 1-bar level. The CH4 emission is quite unexpected and shows a maximum of emission close to the equator. In this work we present the distribution of CH4 and H3+ as observed at limb from December 2018 to September 2020 with the imaging subsystem of JIRAM. Their vertical distribution, obtained from simultaneous spectral measurements, is also shown. Temperature and volume mixing ratio (VMR) of the two species, retrieved using the spectral region between 3 and 4 μm (Dinelli et al. 2017, 2019) are discussed and compared with previous measurements.


The project JIRAM is funded by the Italian Space Agency.



Adriani A. Filacchione G., Di Iorio T., et al. (2014). JIRAM, the Jovian infrared Auroral mapper. Space Sci. Rev. 213, 393,

Dinelli, B.M., et al. (2017), Preliminary Results from the JIRAM Auroral Observations taken during the first Juno orbit: 1 - Methodology and Analysis Applied to the Jovian Northern Polar Region, Geophys. Res. Lett., doi:10.1002/2017GL072929.

Dinelli B.M., Adriani A., Mura A., Altieri F., Migliorini A., Moriconi M.L., (2019). JUNO/JIRAM’s view of Jupiter’s H3+ emissions, Phil. Trans. R. Soc.

How to cite: Migliorini, A., Dinelli, B. M., Moriconi, M., Altieri, F., Castagnoli, C., Mura, A., Adriani, A., Sordini, R., Atreya, S., Tosi, F., Bolton, S., Piccioni, G., Grassi, D., Moirano, A., Noschese, R., Cicchetti, A., Sindoni, G., Plainaki, C., and Olivieri, A.: Properties of H3+ and CH4 at mid and equatorial latitudes in the Jovian atmosphere, observed with JIRAM on Juno, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8184,, 2021.

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