Extended Data Figure 1 : Evolution of HCl in the Earth’s atmosphere and comparison with KASIMA model results.

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

Extended Data Figure 1

a, The long-term total column time series of HCl at Jungfraujoch (running average with a 3-yr integration length, step of 1 month; in red, left scale, in molecules per cm2) and the global total tropospheric chlorine volume mixing ratio (blue curve, right scale). Lower panels display the running average total column time series (1997–2011) of HCl at Ny-Ålesund (b), Jungfraujoch (c) and Lauder (d), derived from the NDACC–FTIR observations and from the KASIMA run (grey). The thin red lines correspond to the ±2 standard error of the mean range. The vertical dashed lines identify the occurrence of the minimum total columns at the Northern Hemisphere sites, in July 2007.