The Antarctic ozone hole during 2017

• Published in: Journal of Southern Hemisphere Earth Systems Science
• Main Authors: Klekociuk, AR, Tully, MB, Krummel, PB, Evtushevsky, O, Kravchenko, V, Henderson, SI, Alexander, SP, Querel, RR, Nichol, S, Smale, D, Milinevsky, GP, Grytsai, A, Fraser, PJ, Xiangdong, Z, Gies, HP, Schofield, R, Shanklin, JD
• Format: Article in Journal/Newspaper
• Language: English
• Published: Australia Bureau of Meteorology 2020
• Subjects: ozone; stratosphere; Antarctic; The Antarctic; Antarc*
• Online Access: https://eprints.utas.edu.au/33896/; https://eprints.utas.edu.au/33896/2/134273%20-%20The%20Antarctic%20ozone%20hole%20during%202017.pdf; http://www.bom.gov.au/jshess/index.shtml

We review the 2017 Antarctic ozone hole, making use of various meteorologicalreanalyses, and in-situ, satellite and ground-based measurements of ozone andrelated trace gases, and ground-based measurements of ultraviolet radiation. The2017 ozone hole was associated with relatively high ozone concentrations overthe Antarctic region compared to other years, and our analysis ranks it in thesmallest 25% of observed ozone holes in terms of size. The severity of stratosphericozone loss was comparable with that which occurred in 2002 (when thestratospheric vortex exhibited an unprecedented major warming) and most yearsprior to 1989 (which were early in the development of the ozone hole). Disturbancesto the polar vortex in August and September that were associated with intervalsof anomalous planetary wave activity resulted in significant erosion of thepolar vortex and the mitigation of the overall level of ozone depletion. The enhancedwave activity was favoured by below-average westerly winds at highsouthern latitudes during winter, and the prevailing easterly phase of the Quasi-Biennial Oscillation (QBO). Using proxy information on the chemical makeup ofthe polar vortex based on analysis of nitrous oxide and the likely influence of theQBO, we suggest that the concentration of inorganic chlorine, which plays a keyrole in ozone loss, was likely similar to 2014 and 2016, when the ozone hole waslarger than in 2017. Overall, we find that the overall severity of Antarctic ozoneloss in 2017 was largely dictated by the timing of the disturbances to the polarvortex rather than interannual variability in the level of inorganic chlorine.