Ozone anomalies over polar regions during the stratospheric warming events

• Main Authors: Shi, Guochun, Krochin, Witali, Sauvageat, Eric, Stober, Gunter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2024
• Subjects: article; Verlagsveröffentlichung; Arctic; Svalbard; Ny-Ålesund; Merra; Ny Ålesund
• Online Access: https://doi.org/10.5194/egusphere-2024-65; https://noa.gwlb.de/receive/cop_mods_00072206; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00070432/egusphere-2024-65.pdf; https://egusphere.copernicus.org/preprints/2024/egusphere-2024-65/egusphere-2024-65.pdf

The impact of major sudden stratospheric warming (SSW) events and early final stratospheric warming (FSW) events on ozone variations in the middle atmosphere in the Arctic is investigated by performing microwave radiometer measurements above Ny-Ålesund, Svalbard (79° N, 12° E) with GROMOS-C. The retrieved daily ozone profiles during SSW and FSW events in the stratosphere and lower mesosphere at 20–70 km from microwave observations are cross-compared to MERRA-2 and MLS. The vertically resolved structure of polar ozone anomalies relative to the climatologies derived from GROMOS-C, MERRA-2, and MLS shed light on the consistent pattern in the evolution of ozone anomalies during both types of events. For SSW events, ozone anomalies are positive throughout all altitudes within 30 days after the onset, followed by negative anomalies descending downward in the middle stratosphere. However, positive anomalies in the middle and lower stratosphere and negative in the upper stratosphere at onset are followed by negative anomalies with descending in the middle stratosphere and positive anomalies in the upper stratosphere during FSW events. We document the underlying dynamical and chemical mechanisms that are responsible for the observed ozone anomalies in the entire life cycle of SSW and FSW events. Polar ozone anomalies in the lower and middle stratosphere undergo a rapid and long-lasting increase of more than 1 ppmv close to SSW onset, which is attributed to the dynamical processes of the horizontal eddy effect and vertical advection. This response pattern for FSW events is associated with the combined effects of dynamical and chemical terms, which reflect the photochemical processes counteracted partially by positive horizontal eddy transport, in particular in the middle stratosphere. Here, we contrast results from MERRA-2 reanalysis and chemistry-climate models to quantify the impact of dynamical and chemical processes on ozone anomalies during SSW and FSW events. In addition, we find that the variability in polar total ...