Abstract
Abstract. Middle atmospheric ozone, water vapour and zonal and meridional wind profiles have been measured with the two ground-based microwave radiometers GROMOS-C and MIAWARA-C. The instruments have been located at the Arctic research base AWIPEV at Ny-Ålesund, Svalbard (79∘ N, 12∘ E), since September 2015. GROMOS-C measures ozone spectra in the four cardinal directions with an elevation angle of 22∘. This means that the probed air masses at an altitude of 3 hPa (37 km) have a horizontal distance of 92 km to Ny-Ålesund. We retrieve four separate ozone profiles along the lines of sight and calculate daily mean horizontal ozone gradients which allow us to investigate the small-scale spatial variability of ozone above Ny-Ålesund. We present the evolution of the ozone gradients at Ny-Ålesund during winter 2018/2019, when a major sudden stratospheric warming (SSW) took place with the central date at 2 January, and link it to the planetary wave activity. We further analyse the SSW and discuss our ozone and water vapour measurements in a global context. At 3 hPa we find a distinct seasonal variation of the ozone gradients. The strong polar vortex during October and March results in a decreasing ozone volume mixing ratio towards the pole. In November the amplitudes of the planetary waves grow until they break in the end of December and an SSW takes place. From November until February ozone increases towards higher latitudes and the magnitude of the ozone gradients is smaller than in October and March. We attribute this to the planetary wave activity of wave numbers 1 and 2 which enabled meridional transport. The MERRA-2 reanalysis and the SD-WACCM model are able to capture the small-scale ozone variability and its seasonal changes.
Highlights
In the Arctic, the polar vortex dominates the dynamics of the wintertime middle atmosphere
The reversal of the latitudinal temperature gradient at 10 hPa was accompanied by a reversal of the zonal mean zonal wind between 60 and 90◦ N which classifies the warming event as a major sudden stratospheric warming according to the definition of McInturff (1978)
We presented the co-located observations of middleatmospheric ozone, water vapour and zonal and meridional wind profiles during the Arctic winter 2018/2019 and discussed the small-scale spatial variability of ozone at an altitude of 37 km (3 hPa)
Summary
In the Arctic, the polar vortex dominates the dynamics of the wintertime middle atmosphere. F. Schranz et al.: Small-scale variability of stratospheric ozone during the SSW 2018/2019. With the measurements from the GROMOS-C ground-based microwave radiometer we are for the first time able to investigate the variability of ozone on small spatial scales. Measurements of the spatial variability of trace gases on scales of a few hundred kilometres are rare For ozone it was analysed by Sparling et al (2006) in the upper troposphere and lower stratosphere to investigate the impact of smallscale variability on satellite data validation. To support the discussion of the small-scale ozone gradients, we analyse the SSW which took place in the beginning of January 2019 and present the measurements from our microwave radiometers in a global context.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
