No abstract

The Umkehr observations over Kyiv (Ukraine) and Antarctic Peninsula areas were processed for the first time to retrieve and analyse the vertical distribution of ozone. The Umkehr observations have been pre-processed using the UMK92 software package proposed by the World Ozone and UV-radiation Data Centre (WOUDC). The set of the calculated vertical ozone profiles for Kyiv–Goloseyev station (2011–2020) and Akademik Vernadsky station (2005–2009) has been obtained. Analysis of ozone profiles observed with Dobson spectrophotometer D040 indicates that the maximum ozone concentration is located in the altitude range of 15–25 km with an average height of 19.8 ± 1.4 km. It corresponds to the layer of maximum ozone concentration in the mid-latitude stratosphere. The maximum ozone partial content in Dobson Units per the layers (DU/layer) with thickness of 5 km altitude for most of the years are of 60–80 DU/layer. There are also days with the maximum ozone content significantly larger than an average. A characteristic feature of the profiles is that the lower ozone content occur in summer and autumn months in the range of 60–75 DU/layer. The winter and spring profiles demonstrate higher ozone values at the maximum. To analyse the vertical profiles of ozone in Antarctic Peninsula area, we use Umkehr data from observations at the Akademik Vernadsky station with the Dobson D123 spectrophotometers in 2005–2009. The data processing and the calculation of the vertical ozone profiles was provided according to the methodology developed at the Kyiv–Goloseyev station. It is shown that the ozone profiles at the Akademik Vernadsky station vary in a wide range of values of the maximum ozone concentration from 40 to 110 DU/layer. Ozone content at maximum of vertical distribution was changing dramatically from day to day in the Antarctic region during the ozone hole period.

We examine the zonal wavenumber spectrum of planetary (Rossby) waves in the atmosphere above Antarctica in each of two contrasting years: in 2019, when there was a sudden stratospheric warming (SSW), and in 2020 when the Antarctic stratospheric vortex was unusually strong and long-lived. The ozone hole (OH) is developed over Antarctica in spring, and its state depends on disturbances of the stratospheric polar vortex by planetary waves (PW). Our analysis uses data on the distribution of the total ozone column from the Ozone Monitoring Instrument on the Aura satellite and ground-based measurements from the Dobson spectrophotometer at the Ukrainian Antarctic Akademik Vernadsky station in Antarctica. The 2019 SSW strongly displaced the Antarctic vortex off-pole and aided the breakdown of the ozone hole. The SSW occurred during the peak activity of quasi-stationary planetary wave-1, which was enhanced at the time of the warming by the large amplitude of traveling wave-2. In the spring of 2020, the stratospheric polar vortex was relatively undisturbed, allowing the OH area to attain a size close to its historical maximum. A factor in 2020 that aided the stability of the vortex was the relatively small amplitude of wave-1. The stability was maintained despite regular periods when the amplitude of traveling wave-2 attained or even exceeded values around the time of the SSW in 2019. We find that a factor contributing to the differences between the wave effects in the two years is the dynamics of the quasi-stationary wave-1. Anticorrelation of the wave-1 and wave-2 amplitudes near the edge of the vortex was clearly observed in 2020, which can be caused by the transfer of planetary wave energy between different spectral wave components, unlike the situation in 2019.