Figure S1 . Variation of (a) N2O, (b) HNO3, (c) HCl, (d) ClO and (e) O3 volume mixing ratio (vmr) from 2004-2020 from Microwave Limb Sounder (MLS) observations and model run CNTL averaged from 63oN-90oN equivalent latitude at 480 K (approx. 18 km). The model was sampled daily at the same local time as the MLS observations. Panels (c)-(e) also show results from simulation ODS95; these results are not included in panels (a) and (b) as they are indistinguishable from simulation CNTL.