Comparison between model and observed VMRs of HCl (left) and water vapour (right) for a representative case where the modelled HCl VMR profile is consistent with the observed profile from ACS MIR. Model profiles are averaged over the 5° L_S interval containing the ACS observation. The standard deviation represents the variability of the computed profiles within this interval. The plots correspond to the ACS MIR occultation 003308_N2_E_P1_11_F, located at latitude 57.14°N, longitude 149.68°E, 234.30° L_S, LT = 8.33 h in MY 34.