Simulation of the record Arctic stratospheric ozone depletion in 2020
<p>In Arctic winter/spring 2019/2020, the stratospheric temperatures&#160; were exceptionally low until early April and the polar vortex was&#160; very stable. &#160;As a consequence, significant chemical ozone depletion&#160; occurred in Northern polar regions in spring 2020. &#160;Here, we present&#160; simulations by the Chemical Lagrangian Model of the Stratosphere&#160; (CLaMS) that address the development of chlorine compounds and&#160; ozone in the polar stratosphere in 2020. &#160;The simulation reproduces&#160; relevant observations of ozone and chlorine compounds, as shown by&#160; comparisons with data from Microwave Limb Sounder (MLS), Atmospheric&#160; Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS),&#160; in-situ ozone sondes and the Ozone Monitoring Instrument (OMI).&#160; Although the concentration of chlorine and bromine compounds in the&#160; polar stratosphere has decreased by more than 10% compared to the&#160; peak values around the year 2000, the meteorological conditions in&#160; winter/spring 2019/2020 caused an unprecedented ozone depletion. The&#160; simulated lowest ozone mixing ratio was around 0.05 ppmv and the&#160; calculated partial ozone column depletion in the vortex core in the&#160; lower stratosphere reached 141 Dobson Units between 350 and 600 K&#160; potential temperature, which is more than the&#160; loss in the years 2011 and 2016 which until 2020 had seen the&#160; largest Arctic ozone depletion on record.</p>