Persistence of the modeled temperature discrepancy at depth

Determine whether the discrepancy between the meridional temperature structure predicted by the radiative-convective model of Milcareck et al. and the Voyager 2 observations persists at deeper atmospheric levels in Uranus and Neptune.

Background

The thermochemical model requires an upper-tropospheric temperature boundary condition that is extrapolated into the deeper atmosphere. The paper compares disk-averaged temperatures from Spitzer and Voyager 2 with meridional temperature profiles predicted by an independent radiative-convective model. Although the modeled profiles are consistent with disk-averaged measurements, they disagree with the Voyager 2 temperature structure at pressures between approximately 0.1 and 0.4 bars. Because the Voyager 2 structure is extrapolated below the tropopause, it is unresolved whether the discrepancy also applies at the deeper levels relevant to the oxygen-abundance retrievals.

References

It is unclear whether this discrepancy remains true at deeper levels, as the Voyager 2 temperature structure data is only extrapolated below the tropopause.

— Contrasting C/O ratios in Uranus and Neptune from disequilibrium chemistry: A clue to distinct evolutionary pathways?  (2609.05326 - Briand et al., 4 Sep 2026) in Section 2.3, subsection “Temperature extrapolation”