On the ambiguous nature of the 11-year solar cycle signal in upper stratospheric ozone

Up to now our understanding of the 11-year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the SAGE II (v6.2) data record which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone-temperature anti-correlation. New simulations from a state-of-art 3-D chemical transport model show a small SCS in the upper stratosphere which is in agreement with SAGE v7.0 data, and the shorter HALOE and MLS records. However, despite these improvements in the SAGE II data, there are still large in current observational and meteorological reanalysis datasets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.