Small-scale variability of stratospheric ozone during the SSW 2018/2019 observed at Ny-Ålesund, Svalbard

• Main Authors: Schranz, Franziska, Hagen, Jonas, Stober, Gunter, Hocke, Klemens, Murk, Axel, Kämpfer, Niklaus
• Format: Text
• Language: English
• Published: 2019
• Subjects: Arctic; Merra; Ny-Ålesund; Svalbard; Ny Ålesund
• Online Access: https://doi.org/10.5194/acp-2019-1093; https://www.atmos-chem-phys-discuss.net/acp-2019-1093/

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 are 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 airmasses 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. In winter 2018/2019 a major sudden stratospheric warming (SSW) took place with the central date at 2 January. We present the ozone, water vapour and wind measurements of the winter 2018/2019 and discuss the signatures of the SSW in a global context. We further present the evolution of the ozone gradients at Ny-Ålesund and link it to the planetary wave activity. At 3 hPa we find a distinct seasonal variation of the ozone gradients. In October and March a strong polar vortex leads to ozone decreases 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 the ozone gradients mostly point to higher latitudes and the magnitude is smaller than in October and March. We attribute this to the planetary wave activity of wave number 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.