Trends in polar ozone loss since 1989: potential sign of recovery in the Arctic ozone column

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Pazmino, Andrea, Goutail, Florence, Godin-Beekmann, Sophie, Hauchecorne, Alain, Pommereau, Jean-Pierre, Chipperfield, Martyn, P, Feng, Wuhu, Lefèvre, Franck, Lecouffe, Audrey, van Roozendael, Michel, Jepsen, Nis, Hansen, Georg, Kivi, Rigel, Strong, Kimberly, Walker, Kaley, A
• Other Authors: STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Earth and Environment Leeds (SEE), University of Leeds, NERC National Centre for Earth Observation (NCEO), Natural Environment Research Council (NERC), National Centre for Atmospheric Science Leeds (NCAS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Danish Meteorological Institute (DMI), Norwegian Institute for Air Research (NILU), Faculty of Informatics and Mathematics (FMI), Fakultät für Informatik und Mathematik, Department of Physics Toronto, University of Toronto
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarc*; Antarctic; Arctic
• Online Access: https://insu.hal.science/insu-04096452; https://insu.hal.science/insu-04096452v2/document; https://insu.hal.science/insu-04096452v2/file/acp-23-15655-2023.pdf; https://doi.org/10.5194/acp-23-15655-2023

International audience Ozone depletion over the polar regions is monitored each year by satellite- and ground-based instru- ments. In this study, the vortex-averaged ozone loss over the last 3 decades is evaluated for both polar regions using the passive ozone tracer of the chemical transport model TOMCAT/SLIMCAT and total ozone observa- tions from Système d’Analyse par Observation Zénithale (SAOZ) ground-based instruments and Multi-Sensor Reanalysis (MSR2). The passive-tracer method allows us to determine the evolution of the daily rate of column ozone destruction and the magnitude of the cumulative column loss at the end of the winter. Three metrics are used in trend analyses that aim to assess the ozone recovery rate over both polar regions: (1) the maximum ozone loss at the end of the winter, (2) the onset day of ozone loss at a specific threshold, and (3) the ozone loss residuals computed from the differences between annual ozone loss and ozone loss values regressed with respect to sunlit volume of polar stratospheric clouds (VPSCs). This latter metric is based on linear and parabolic regressions for ozone loss in the Northern Hemisphere and Southern Hemisphere, respectively. In the Antarctic, metrics 1 and 3 yield trends of −2.3 % and −2.2 % per decade for the 2000–2021 period, significant at 1 and 2 standard deviations (σ ), respectively. For metric 2, various thresholds were considered at the total ozone loss values of 20%, 25%, 30%, 35%, and 40%, all of them showing a time delay as a function of year in terms of when the threshold is reached. The trends are significant at the 2σ level and vary from 3.5 to 4.2 d per decade between the various thresholds. In the Arctic, metric 1 exhibits large interannual variability, and no significant trend is detected; this result is highly influenced by the record ozone losses in 2011 and 2020. Metric 2 is not applied in the Northern Hemisphere due to the difficulty in finding a threshold value in enough of the winters. Metric 3 pro- vides a negative trend in ...