Examples of temperature profiles used in this study. Our nominal profile is displayed in red. The thermal profiles displayed in blue correspond to cases in which the temperature at pressures lower than 2 mbar is increased or decreased with 1-K steps from −14 to +15 K. The deviations from our nominal thermal profile are initiated at 10 mbar to smooth the transition from the nominal profile at higher pressures toward the modified thermal profile at lower pressures.