Arctic Tropospheric Ozone Trends

• Published in: Geophysical Research Letters
• Main Authors: Law, Kathy S., Hjorth, Jens, L, Pernov, Jakob, B, Whaley, Cynthia, H, Skov, Henrik, Coen, Martine, Collaud, Langner, Joakim, Arnold, Stephen, R, Tarasick, David, Christensen, Jesper, Deushi, Makoto, Effertz, Peter, Faluvegi, Greg, Gauss, Michael, Im, Ulas, Oshima, Naga, Petropavlovskikh, Irina, Plummer, Da, Tsigaridis, Kostas, Tsyro, Svetlana, Solberg, Sverre, Turnock, Stephen
• Other Authors: TROPO - 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 Environmental Science Roskilde (ENVS), Aarhus University Aarhus, Extreme Environments Research Laboratory (EERL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Environment and Climate Change Canada (ECCC), Federal Office of Meteorology and Climatology MeteoSwiss, Swedish Meteorological and Hydrological Institute (SMHI), Institute for Climate and Atmospheric Science Leeds (ICAS), School of Earth and Environment Leeds (SEE), University of Leeds-University of Leeds, Meteorological Research Institute Tsukuba (MRI), Japan Meteorological Agency (JMA), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder -National Oceanic and Atmospheric Administration (NOAA), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Center for Climate Systems Research New York (CCSR), Columbia University New York, NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), Norwegian Meteorological Institute Oslo (MET), Norwegian Institute for Air Research (NILU), Met Office Hadley Centre (MOHC), United Kingdom Met Office Exeter, ANR-21-CE01-0017,CASPA,Sources d'aérosols et processus liés au climat dans l'Arctique(2021)
• Format: Article in Journal/Newspaper
• Language: English
• Published: CCSD 2023
• Subjects: [SDU]Sciences of the Universe [physics]; Arctic; Alaska
• Online Access: https://insu.hal.science/insu-04298754; https://insu.hal.science/insu-04298754v1/document; https://insu.hal.science/insu-04298754v1/file/Geophysical%20Research%20Letters%20-%202023%20-%20Law%20-%20Arctic%20Tropospheric%20Ozone%20Trends.pdf; https://doi.org/10.1029/2023GL103096

International audience Observed trends in tropospheric ozone, an important air pollutant and short-lived climate forcer (SLCF), are estimated using available surface and ozonesonde profile data for 1993-2019, using a coherent methodology, and compared to modeled trends (1995-2015) from the Arctic Monitoring Assessment Program SLCF 2021 assessment. Increases in observed surface ozone at Arctic coastal sites, notably during winter, and concurrent decreasing trends in surface carbon monoxide, are generally captured by multi-model median trends. Wintertime increases are also estimated in the free troposphere at most Arctic sites, with decreases during spring months. Winter trends tend to be overestimated by the multi-model medians. Springtime surface ozone increases in northern coastal Alaska are not simulated while negative springtime trends in northern Scandinavia are not always reproduced. Possible reasons for observed changes and model performance are discussed including decreasing precursor emissions, changing ozone dry deposition, and variability in large-scale meteorology. Plain Language Summary The Arctic is warming much faster than the rest of the globe due to increases in carbon dioxide, and other trace constituents like ozone, also an air pollutant. However, improved understanding is needed about long-term changes or trends in Arctic tropospheric ozone. A coherent methodology is used to identify trends in surface and regular profile measurements over the last 20-30 years, and results from six chemistry-climate models. Increases in observed ozone are found at the surface and in the free troposphere during winter in the high Arctic. Paradoxically, decreases in nitrogen oxide emissions at mid-latitudes appear to be leading to increases in ozone during winter, but associated increases in Arctic tropospheric ozone tend to be overestimated in the models. Increases are also found at the surface in northern Alaska during spring but not reproduced by the models. The causes are unknown but could be related to ...