Spatial and temporal variations in the CH4 homopause altitude at Jupiters mid-to-high latitudes - Observatoire de Paris Access content directly
Conference Papers Year : 2021

Spatial and temporal variations in the CH4 homopause altitude at Jupiters mid-to-high latitudes

James Sinclair
  • Function : Author
Thomas Greathouse
  • Function : Author
Rohini Giles
  • Function : Author
Matthew Richter
  • Function : Author
Maisie Rashman
  • Function : Author
Curtis Dewitt
  • Function : Author
Julianne Moses
  • Function : Author
Thierry Fouchet
Vincent Hue
Glenn Orton
  • Function : Author
Leigh Fletcher
  • Function : Author
Patrick Irwin
  • Function : Author


Jupiters magnetosphere and the external space environment strongly influence the thermal structure, chemistry and dynamics of the neutral atmosphere. Using TEXES (Texas Echelon Cross Echelle Spectrograph) observations measured in April and August 2019 from the IRTF, we demonstrated that the CH4 homopause altitude, henceforth CHA, was 70 130 km higher in altitude inside Jupiters northern main auroral oval compared to elsewhere on the planet (Sinclair et al., 2020, PSJ 1, 85). This suggests energy from Jupiters magnetosphere ultimately drives vertical winds and turbulence, which transports CH4 and its photochemical by-products to higher altitudes. The CHA is also an uncertain degree of freedom in the analysis of Jupiters ultraviolet auroral emissions, which are under current investigation by the Juno mission, as well as by Hubble and Hisaki. The goal of this work is to provide independent and stringent constraints on the CHA to best support Junos investigation of the ultraviolet auroral emissions and their connection to magnetospheric dynamics. We present an analysis of high-resolution mid-infrared spectra recorded by SOFIA-EXES on June 8 18, 2021 and IRTF-TEXES on June 28-29, 2021, which provide significant advances on previous work presented by Sinclair et al., 2020. In contrast to the TEXES observations in 2019, both sets of data in 2021 sample longitudes inside the southern auroral oval, which allows the CHA to be constrained in this region. A comparison of the results inside the northern main oval with those measured in 2019 allows the temporal variability of the CHA inside Jupiters northern auroral oval to be quantified. Although at a coarser spatial resolution, EXES measurements probe higher in Jupiters stratosphere/mesophere, which is expected to provide more stringent upper limits on the CHA in Jupiters main ovals. In addition, observations in both 2019 and 2021 will be re-analyzed with an updated model grid that extends to lower CHAs. This provides more stringent constraints on the CHA derived outside the main ovals, which in turn allows the contrast in CHA inside and outside the main auroral ovals to be more accurately quantified.
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Dates and versions

obspm-03903788 , version 1 (16-12-2022)



James Sinclair, Thomas Greathouse, Rohini Giles, Matthew Richter, Maisie Rashman, et al.. Spatial and temporal variations in the CH4 homopause altitude at Jupiters mid-to-high latitudes. AGU Fall Meeting, Dec 2021, Nouvelle-Orléans, United States. ⟨obspm-03903788⟩
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