The pronounced positive trend in the Southern Annular Mode (SAM), previously driven by ozone depletion, has markedly weakened since the early 21st century due to ozone recovery. However, whether state-of-the-art climate models capture the changes in SH atmospheric circulation remains unclear. In this study, we evaluate 37 CMIP6 models on their simulation of the austral summer SAM trend across the ozone depletion period (1979–2000) and the recovery period (2001–2025). Results show that the majority of models capture the observed strengthening of the SAM before 2000 and the subsequent moderation of the trend afterward, despite a general underestimation of the trend magnitude. Employing a detection and attribution analysis based on outputs from the DAMIP, we identify stratospheric ozone as the primary driver of the observed extratropical circulation changes since 2000, with GHGs playing an antagonistic role. Furthermore, we find that the estimated intervals of internal variability can be modulated by the selection of pre-industrial control (piControl) segments, which highlights the limitation in current attribution analysis that requires careful consideration.
WANG et al. (Sun,) studied this question.