EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2025-2527 Recent Advances in Aerosol Optical Depth Measurements in Polar Regions: Insights from the Polar-AOD Program Pulimeno Simone https://orcid.org/0000-0002-5198-122X 1 2 Lupi Angelo 2 Vitale Vito 2 Frangipani Claudia 2 Toledano Carlos https://orcid.org/0000-0002-6890-6648 3 Kazadzis Stelios https://orcid.org/0000-0003-1031-0216 4 Kouremeti Natalia 4 Ritter Christoph 5 Graßl Sandra https://orcid.org/0000-0001-8687-833X 5 Stebel Kerstin https://orcid.org/0000-0002-6935-7564 6 Fioletov Vitali https://orcid.org/0000-0002-2731-5956 7 Abboud Ihab 7 Blindheim Sandra 8 Ma Lynn 9 O’Neill Norm 10 Sobolewski Piotr 11 Gupta Pawan https://orcid.org/0000-0002-0979-472X 12 Lind Elena 12 Eck Thomas F. 12 Hyvärinen Antti 13 Aaltonen Veijo 13 Kivi Rigel https://orcid.org/0000-0001-8828-2759 14 Csavina Janae 15 Kabanov Dmitry 16 Sakerin Sergey M. 16 Sidorova Olga R. 17 Stone Robert S. 18 26 Telg Hagen 18 Riihimaki Laura https://orcid.org/0000-0002-1794-3860 18 Cordero Raul R. https://orcid.org/0000-0001-7607-7993 19 20 Radenz Martin https://orcid.org/0000-0002-7771-033X 21 Engelmann Ronny https://orcid.org/0000-0003-4225-9961 21 Van Roozendal Michel 22 Chaikovsky Anatoli 23 Goloub Philippe 24 Hisamitsu Junji 25 Mazzola Mauro https://orcid.org/0000-0002-8394-2292 2 Ca’ Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, 30123 Venice, Italy National Research Council, Institute of Polar Sciences, 40129 Bologna, Italy University of Valladolid, 47002 Valladolid, Spain Physikalisch-Meteorologisches Observatorium Davos, 7260 Davos, Switzerland Alfred Wegener Institute for Polar and Marine Research, 14473 Potsdam, Germany NILU, 2007 Kjeller, Norway Environment and Climate Change Canada, M3H 5T4 Ontario, Canada Andøya Rocket Range, 8480 Andenes, Norway Environmental Science and Technologies, Brookhaven National Laboratory, 11973 New York, USA Sherbrooke University, QC J1N 3C6 Quebec, Canada Polish Academy of Sciences, Institute of Geophysics, 01-452 Warsaw, Poland NASA Goddard Space Flight Center, 20771 Greenbelt, USA Finnish Meteorological Institute, 00101 Helsinki, Finland Finnish Meteorological Institute, 99600 Sodankylä, Finland National Ecological Observatory Network, 80301 Boulder, USA Zuev Institute of Atmospheric Optics, Russian Academy of Science, 634055 Tomsk, Russia Arctic and Antarctic Research Institute, 199397 St Petersburg, Russia National Oceanic and Atmospheric Administration, 20230 Washington, USA University of Groningen, 8911 CE Leeuwarden, The Netherlands Santiago de Chile University, 9170022 Santiago, Chile Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany Belgian Institute for Space Aeronomy, 1180 Brussels, Belgium Institute of Physics, National Academy of Sciences of Belarus, 220072 Minsk, Belarus University of Lille, Atmospheric Optics Laboratory, 59655 Villenueve d’Ascq Cedex, France Japan Meteorological Agency, 105-8431 Tokyo, Japan retired 04 09 2025 2025 1 58 Copyright: © 2025 Simone Pulimeno et al. 2025 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2527/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2527/egusphere-2025-2527.pdf

A multi-year analysis of aerosol optical depth (AOD, &tau;) and Ångström exponent (&alpha;) was conducted using ground-based photometer data from 15 Arctic and 11 Antarctic sites. Extending the dataset of Tomasi et al. 2015 through December 2024, the study incorporates stellar and lunar photometric observations to fill data gaps during the polar night. Daily mean values of &tau; at 0.500 <em>&mu;</em>m and &alpha; (0.440&ndash;0.870 <em>&mu;</em>m) were used to derive monthly means and seasonal histograms.</p> <p>In the Arctic, persistent haze events in winter and early spring lead to peak &tau; values. A decreasing trend in Arctic &tau; suggests the impact of European emission regulations, while biomass-burning aerosols are becoming more significant. In Antarctica, &tau; increases from the plateau to the coast. Fine-mode aerosols dominate in summer-autumn, while coarse-mode particles are more prevalent in winter-spring. Shipborne photometer data align well with ground-based measurements, confirming the reliability of mobile observations.</p> <p>Trend analyses using the Mann-Kendall test and Theil-Sen regression indicate a significant negative trend in &tau; at Andenes (-2.43 % per year), likely driven by reduced anthropogenic emissions. Antarctic stations such as Syowa and South Pole show positive trends (+3.84 % and +3.54 % per year), though these are subject to uncertainties from data limitations and instrument changes.</p> <p>This work contributes to the Polar-AOD network (<a href="https://polaraod.net/" target="_blank" rel="noopener">https://polaraod.net/</a>; last access 15/05/2025), enhancing the understanding of aerosol variability and long-term trends in polar regions while promoting open data access for the scientific community.