Quantitative Investigations of the Unprecedented Stratospheric Ozone Depletion During Spring 2020 in the Arctic

Description

The severe depletion of Arctic lower stratospheric (ALS) ozone in spring 2020 has attracted considerable attention. However, the dynamic and chemical contributions of various source regions to ALS ozone levels in spring 2020 remains unclear. To enhance our understanding of Arctic stratospheric ozone, in this study, we used tagged ozone tracers from the specified dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) to quantify the dynamic and chemical contributions from different source regions to the ALS ozone levels in the winter and spring of 2019/2020. The SD-WACCM simulation results indicated that the recovery of ozone after warming of the ALS (April 19-May 19) mainly occurred due to advective transport. The northern mid-latitudinal lower stratosphere and tropical lower stratosphere had the largest advective contributions to the ALS ozone, with 49.71 and 31.00 DU, respectively. Compared with other years, the combination of an unusually weak dynamic ozone supply and severe chemical depletion contributed to the record-low ALS ozone in spring 2020. The persistent and strong polar vortex before the warming (March 18-April 18) resulted in an unusually weak ozone supply, whereas ozone from lower latitudes was gradually transported to the Arctic after the warming. Clear chlorine and bromine activations were simulated during the winter-spring of 2019/2020, and bromine activation continued until June, leading to severe ozone chemical depletion. Our findings can be used to enhance predictions of low ozone events within the Arctic in future years and enhance future research on Arctic stratospheric ozone. sd-waccm-o3.nc, sd-waccm-T.nc, and o3-halogen.nc are average ozone, temperature, and halogen profiles over the Arctic, respectively. map-sd-waccm-o3.nc is average ozone mixing ratios from SD-WACCM in the Arctic region in Interval 1. The plotted ipynb code runs on python version 3.8.8. The data.xlsx includes six sheets. Sheet1 is daily total advective and chemical tendencies. Sheet2 is cumulative advective and chemical tendencies of ozone tracers in the seven source regions of the ALS in Intervals 1 and 2. Sheet3 is daily total advective and chemical tendencies in 2005, 2006, 2009,2011 and 2020. Sheet4 is average O3, ClO, BrO mixing ratios at 70 hPa in the Arctic and the severely ozone-depleted region. Sheet5 is average contributions of the seven regions to ALS ozone. Sheet6 is cumulative advective and chemical tendencies of ozone tracers in the seven source regions of the severely ozone-depleted region lower stratosphere in Intervals 1 and 2.

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