Observed stratospheric mean age decrease consistent with circulation acceleration (opens in new tab)

The Brewer–Dobson circulation largely determines the distribution of key trace gases and aerosols in the stratosphere and is projected to accelerate under climate change in chemistry-climate models simulations. However, observational constraints based on the mean age of air have suggested weak increases, implying a possible slowdown of the circulation and a discrepancy from model projections. Here we examine changes in the strength of the Northern Hemisphere stratospheric circulation over 199...