Figure S2 . Variation of daily (a) N2O, (b) HNO3, (c) HCl, (d) ClO and (e) O3 volume mixing ratio (vmr) from early December to end of April from 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. The shading indicates the range of values from MLS (blue) and the model (orange). The values for specific years 2010/11, 2018/19 and 2019/20 are shown by the coloured lines (see legend, MLS dashed lines, model solid lines). Note that panel (a) does not show any MLS data.