Research on the unusual spring 2020 Arctic stratospheric ozone depletion above Ny-Ålesund, Norway

• Main Authors: Li, Qidi, Luo, Yuhan, Qian, Yuanyuan, Pan, Chen, Dou, Ke, Hou, Xuewei, Si, Fuqi, Liu, Wenqing
• Format: Text
• Language: English
• Published: 2023
• Subjects: Arctic; Norway; Ny-Ålesund; Svalbard; Climate change; Ny Ålesund
• Online Access: https://doi.org/10.5194/acp-2022-859; https://acp.copernicus.org/preprints/acp-2022-859/

Of the severe stratospheric ozone depletion events (ODEs) reported over the Arctic, the third and most severe occurred during the spring of 2020; we analyzed the reasons for this event herein. We retrieved the critical indicator ozone vertical column density (VCD) using zenith scattered light differential optical absorption spectroscopy (ZSL-DOAS) located in Ny-Ålesund, Svalbard, Norway. The average ozone VCDs over Ny-Ålesund between March 18 and April 18, 2020, were approximately 274.8 Dobson units (DU), which was only about 64.7 % of that in normal years. The retrieved daily averages of ozone VCDs were compared with satellite observations from Global Ozone Monitoring Experiment 2 (GOME-2), a Brewer spectrophotometer, and a Système d’Analyze par Observation Zénithale (SAOZ) spectrometer at Ny-Ålesund; the resulting Pearson correlation coefficients were relatively high at 0.94, 0.86, and 0.91, with relative deviations of 2.3 %, 3.1 %, and 3.5 %, respectively. Compared with normal years, the 2020 daily peak relative ozone loss was approximately 44.3 %. During the 2020 Arctic spring ODE, the ozone VCDs and potential vorticity (PV) had a negative correlation with their fluctuations, suggesting a clear effect of the polar vortex on stratospheric ozone depletion. To better understand what caused the ozone depletion, we also considered the chemical components of this process in the Arctic winter of 2019/2020 with the specified dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM). The SD-WACCM model results indicated that both ClO and BrO concentrations peaked in late March, which was a critical factor during the ozone depletion observed in Ny-Ålesund. Chlorine activation was clearly apparent during the Arctic spring of 2020, whereas the partitioning of bromine species was different from that of chlorine. By combining observations with modeling, we provide a reliable basis for further research on global climate change due to polar ozone concentrations and the prediction of severe Arctic ozone ...