Recent Sea Surface Temperature Trends Hinder Antarctic Stratospheric Ozone Recovery

Recent reports on anomalously large ozone holes imply the uncertainty of the Antarctic ozone recovery. This study demonstrates that the sea surface temperature (SST) trends during this century hinder the Antarctic ozone recovery under the background of reductions in ozone depleting-substance (ODS) emissions. The observations show a significant recovery of the polar mean (60°S-90°S) total column ozone (TCO) in September during 2000-2021, while the robust ozone loss is found in the middle stratosphere over the South Pacific Ocean during October-November. The numerical experiments reveal that the significant TCO recovery occur throughout austral spring when only ODS emissions reductions are applied in the model. Superposing the SST linear increment in the model causes ozone decreases in the middle stratosphere over South Pacific during October-November, and approximate 46% reductions of the polar mean TCO recovery throughout austral spring. Both reanalysis data and model simulations forced by SST linear increments indicate the weakening of the Antarctic stratospheric planetary wave activity, leading a cooling in stratospheric temperature over the South Pacific and a reduction in local nitric acid. The nitric acid loss results in an increase of the ratios between the active halogens and the halogen reservoirs (ClOx/Clresv, BrOx/Brresv), which promotes ozone depletions.