Modelling wintertime sea-spray aerosols under Arctic haze conditions

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Ioannidis, Eleftherios, Law, Kathy S., Raut, Jean-Christophe, Marelle, Louis, Onishi, Tatsuo, Kirpes, Rachel, M., Upchurch, Lucia, Tuch, Thomas, Wiedensohler, Alfred, Massling, Andreas, Skov, Henrik, Quinn, Patricia, K., Pratt, Kerri, A.
• 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 Earth Sciences Amsterdam, Vrije Universiteit Amsterdam Amsterdam (VU), Department of Chemistry Ann Arbor, University of Michigan Ann Arbor, University of Michigan System-University of Michigan System, NOAA Pacific Marine Environmental Laboratory Seattle (PMEL), National Oceanic and Atmospheric Administration (NOAA), Leibniz Institute for Tropospheric Research (TROPOS), Department of Environmental Science Roskilde (ENVS), Aarhus University Aarhus, Department of Earth and Environmental Sciences Ann Arbor, 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: HAL CCSD 2023
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Arctic; Barrow; Alaska
• Online Access: https://insu.hal.science/insu-03696235; https://insu.hal.science/insu-03696235v2/document; https://insu.hal.science/insu-03696235v2/file/acp-23-5641-2023.pdf; https://doi.org/10.5194/acp-23-5641-2023

International audience Anthropogenic and natural emissions contribute to enhanced concentrations of aerosols in the Arcticwinter and early spring, with most attention being paid to anthropogenic aerosols that contribute to so-calledArctic haze. Less-well-studied wintertime sea-spray aerosols (SSAs) under Arctic haze conditions are the focusof this study, since they can make an important contribution to wintertime Arctic aerosol abundances. Analysis offield campaign data shows evidence for enhanced local sources of SSAs, including marine organics at Utqia ̇gvik(formerly known as Barrow) in northern Alaska, United States, during winter 2014. Models tend to underestimatesub-micron SSAs and overestimate super-micron SSAs in the Arctic during winter, including the base version ofthe Weather Research Forecast coupled with Chemistry (WRF-Chem) model used here, which includes a widelyused SSA source function based on Gong et al. (1997). Quasi-hemispheric simulations for winter 2014 includingupdated wind speed and sea-surface temperature (SST) SSA emission dependencies and sources of marine sea-salt organics and sea-salt sulfate lead to significantly improved model performance compared to observations atremote Arctic sites, notably for coarse-mode sodium and chloride, which are reduced. The improved model alsosimulates more realistic contributions of SSAs to inorganic aerosols at different sites, ranging from 20 %–93 %in the observations. Two-thirds of the improved model performance is from the inclusion of the dependenceon SSTs. The simulation of nitrate aerosols is also improved due to less heterogeneous uptake of nitric acid onSSAs in the coarse mode and related increases in fine-mode nitrate. This highlights the importance of interactionsbetween natural SSAs and inorganic anthropogenic aerosols that contribute to Arctic haze. Simulation of organicaerosols and the fraction of sea-salt sulfate are also improved compared to observations. However, the modelunderestimates episodes with elevated observed concentrations ...