Extended Data Figure 4 : Spatial distribution of the HCl concentration and age-of-air changes.

From: Recent Northern Hemisphere stratospheric HCl increase due to atmospheric circulation changes

Extended Data Figure 4

Mean differences of the HCl concentration (a) and age-of-air (b) between 2010/11 and 2005/06, as a function of altitude and latitude, derived from the KASIMA model simulation. c, Running averages of the mean age-of-air at 50 hPa (thick/thin curve, integration length of 36/6 months), at the same sites as in Fig. 1 (time series at 79° N/45° S have been shifted vertically by −0.75/−0.50 yr). Comparison with age-of-air time series derived from SLIMCAT (see Fig. 4c) indicates that KASIMA provides higher absolute values of mean age-of-air. Note that the upper boundary of KASIMA is at 120 km, yielding higher mean ages, compared to SLIMCAT (upper boundary 60 km).