Reliably constrain Saturn’s stratospheric CO vertical profile from submillimeter line observations

Determine the vertical profile of carbon monoxide (CO) in Saturn’s stratosphere using the CO (J=3-2) line at 345.796 GHz observed with the Submillimeter Array (SMA) and the CO (J=2-1) line at 230.538 GHz observed with the Atacama Large Millimeter/submillimeter Array (ALMA), which could not be reliably constrained due to baseline ripple removal and limited bandpass quality affecting the line-wing information in these datasets.

Background

The authors aim to assess whether Saturn’s 2010–2011 Great Storm perturbed the stratospheric distribution of carbon monoxide and to measure the associated stratospheric winds using interferometric observations of CO with SMA (pre-storm) and ALMA (during the storm).

Accurate retrieval of a vertical profile for CO relies on the integrity of line-wing shapes, but the SMA and ALMA datasets suffered from bandpass limitations and baseline ripple removal that compromised the broad wings of the lines. As a result, the authors adopted a previously derived comet-impact transport profile as a template and scaled it, rather than retrieving a new vertical profile from the data.

References

Also, because of the limited bandpass quality of the SMA data, and to a less pronounced level, of the ALMA data, we cannot fully rely on the broad wing shape of the lines after the baseline ripple removal stage. We thus cannot reliably constrain the CO vertical profile.

— Observations of the temporal evolution of Saturn's stratosphere following the Great Storm of 2010-2011. II. Latitudinal distribution of CO and stratospheric winds  (2601.20359 - Cavalié et al., 28 Jan 2026) in Section 3.1.2 (Subsubsection: Background composition and CO distribution model)