CO mole fraction measured at 0.3 mbar in Saturn’s stratosphere in January 2012 with ALMA as a function of latitude. The mole fractions are derived from fits made at the planet eastern (red line) and western (blue line) limbs with the 220-year-old-comet-impact profile of Cavalié et al. (2010) properly rescaled at each latitude to best fit the data. Error bars indicate the ranges of columns that fit the data with χ²/N<4 (red line for the eastern limb and blue line for the western limb) and χ²/N<9 (orange line for the eastern limb and cyan line for the western limb). The latitude region affected by ring shadowing in the 2012 ALMA data is highlighted with the light yellow box. The latitudinal resolution as a function of latitude is plotted in solid black on the second y-axis.