Springtime stratospheric ozone trends in the Arctic since 1980

The Arctic ozone layer is characterised by high interannual variability, especially in the springtime period, which depends on stratospheric circulation and polar vortex forcing. Since the 1990s, there has been a gradual ozone recovery in the Arctic polar stratosphere. However, the increasing ozone trend may be different in unlike pressure levels of the stratosphere in connection with the ongoing climate change, which is related to the strengthening of the Brewer-Dobson circulation. This strengthening is related to changes in vertical distribution of ozone concentrations in different levels of the stratosphere. The aim of this study is a spatiotemporal analysis of the stratospheric ozone trend at different pressure levels between 10–100 hPa in the spring periods 1980–2023. In the following section, trends of geopotential height, temperature or potential vorticity at pressure levels between 10–100 hPa are analysed in particular. The monthly means of ERA-5 reanalysis layers were utilized. The trend was assessed using linear regression, and its statistical significance was determined using the non-parametric Mann-Kendall test. In March, the statistically significant decreasing trend (p=0.05) of the ozone mass mixing ratio was detected over Siberia at 10 hPa, while at 100 hPa, the statistically significant decreasing trend was registered over eastern Siberia and Greenland. In April, there was a statistically significant increasing trend at 10 hPa over eastern Siberia, and at 100 hPa, the trend over uniform parts of the central Arctic is spatially heterogeneous. In May, a statistically insignificant increasing trend occurred over the Arctic Ocean at 10 hPa, while at 100 hPa statistically significant decreasing trend was registered in the peripheral parts of the Arctic between 60–70°N.