Search

The stratospheric ozone layer, which prevents solar ultraviolet radiation from reaching the surface and thereby protects life on earth, is expected to recover from past depletion during this century due to the impact of the Montreal Protocol. However, how the ozone column over the Arctic will evolve over the next few decades is still under debate. In this study, we found that the ozone level in the Arctic stratosphere at 100–150 hPa during 1998–2018 exhibits a decreasing trend of − 0.12 ± 0.07 ppmv decade–1 from MERRA2, suggesting a continued depletion during this century. About 30% of this ozone depletion is contributed by the second leading mode of sea surface temperature anomalies (SSTAs) over the North Pacific with one month leading and therefore is dynamical in origin. The North Pacific SSTAs associated with this mode tend to result in a weakened Aleutian low, a strengthened Western Pacific pattern and a weakened Pacific–North American pattern, which impede the upward propagation of wavenumber-1 waves into the lower stratosphere. The changes in the stratospheric wave activity may result in decreased ozone in the Arctic lower stratosphere through weakening the Brewer-Dobson circulation. Our findings uniquely linked the recent ozone depletion in the Arctic stratosphere to the North Pacific SSTs and might provide new understanding of how dynamical processes control Arctic stratospheric ozone. [ABSTRACT FROM AUTHOR]

We compare the relationship between the Arctic Oscillation (AO) and ozone concentration in the lower stratosphere over the Arctic during 1980–1994 (P1) and 2007–2019 (P2) in January and February using reanalysis datasets. The out-of-phase relationship between the AO and ozone in the lower stratosphere is significant in January during P1 and February during P2, but it is insignificant in January during P2 and February during P1. The variable links between the AO and ozone in the lower stratosphere over the Arctic in January and February are not caused by changes in the spatial pattern of AO but are related to the anomalies in the planetary wave propagation between the troposphere and stratosphere. The upward propagation of the planetary wave in the stratosphere related to the positive phase of AO significantly weakens in January during P1 and in February during P2, which may be related to negative buoyancy frequency anomalies over the Arctic. When the AO is in the positive phase, the anomalies of planetary wave further contribute to the negative ozone anomalies via weakening the Brewer–Dobson circulation and decreasing the temperature in the lower stratosphere over the Arctic in January during P1 and in February during P2. [ABSTRACT FROM AUTHOR]