Record springtime stratospheric ozone depletion at 80°N in 2020

• Main Authors: Alwarda, Ramina, Bognar, Kristof, Strong, Kimberly, Chipperfield, Martyn, Dhomse, Sandip, Drummond, James, Feng, Wuhu, Fioletov, Vitali, Goutail, Florence, Herrera, Beatriz, Manney, Gloria, Mccullough, Emily, Millan, Luis, Pazmino, Andrea, Walker, Kaley, Wizenberg, Tyler, Zhao, Xiaoyi
• Other Authors: Department of Physics Toronto, University of Toronto, School of Earth and Environment Leeds (SEE), University of Leeds, Department of Physics and Atmospheric Science Halifax, Dalhousie University Halifax, Environment and Climate Change Canada, 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), Department of Physics Socorro, New Mexico Institute of Mining and Technology New Mexico Tech (NMT), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2021
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarc*; Antarctic; Arctic
• Online Access: https://insu.hal.science/insu-03212647; https://doi.org/10.5194/egusphere-egu21-8892

International audience The Arctic winter of 2019-2020 was characterized by an unusually persistent polar vortex and temperatures in the lower stratosphere that were consistently below the threshold for the formation of polar stratospheric clouds (PSCs). These conditions led to ozone loss that is comparable to the Antarctic ozone hole. Ground-based measurements from a suite of instruments at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05°N, 86.42°W) were used to investigate chemical ozone depletion. The vortex was located above Eureka longer than in any previous year in the 20-year dataset and lidar measurements provided evidence of polar stratospheric clouds (PSCs) above Eureka. Additionally, UV-visible zenith-sky Differential Optical Absorption Spectroscopy (DOAS) measurements showed record ozone loss in the 20-year dataset, evidence of denitrification along with the slowest increase of NO2 during spring, as well as enhanced reactive halogen species (OClO and BrO). Complementary measurements of HCl and ClONO2 (chlorine reservoir species) from a Fourier transform infrared (FTIR) spectrometer showed unusually low columns that were comparable to 2011, the previous year with significant chemical ozone depletion. Record low values of HNO3 in the FTIR dataset are in accordance with the evidence of PSCs and a denitrified atmosphere. Estimates of chemical ozone loss were derived using passive ozone from the SLIMCAT offline chemical transport model to account for dynamical contributions to the stratospheric ozone budget.