Biogenic influence on the composition and growth of summertime Arctic aerosol

• Main Authors: Willis, Megan D., Burkart, Julia, Thomas, Jennie L., Koellner, Franziska, Schneider, Johannes, Bozem, Heiko, Hoor, Peter M., Aliabadi, Amir A., Schulz, Hannes, Herber, Andreas B., Leaitch, Richard, Abbatt, Jonathan P. D.
• Other Authors: Department of Chemistry University of Toronto, University of Toronto, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Environmental Engineering Program Guelph, University of Guelph, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Environment and Climate Change Canada
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2016
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Arctic; Aitken; Lancaster Sound; Resolute Bay; black carbon
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-01418724

International audience The summertime Arctic lower troposphere is a relatively pristine background aerosol environment dominated by nucleation and Aitken mode particles. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties and therefore radiative balance and climate. We present aircraft-based observations of submicron aerosol composition from an aerosol mass spectrometer made during the NETCARE 2014 summertime arctic campaign, based in the Canadian High Arctic, at Resolute Bay, NU (74°N). Under stable and regionally influenced atmospheric conditions with low carbon monoxide and black carbon concentrations (< 100 ppbv and < 50 ng/m 3 , respectively), we observed organic aerosol (OA)-to-sulfate ratios ranging from ~0.5 to > 6 with evidence for enhancement within the lower boundary layer. Methanesulfonic acid (MSA), a marker for the contribution of ocean-derived biogenic sulphur, was also observed in submicron aerosol. MSA-to-sulfate ratios ranged from near zero to ~0.3 and tended to increase within the lower boundary layer, suggesting a contribution to aerosol loading from the ocean. In one notable case while flying in the lower boundary layer above open water in Lancaster Sound, we observed growth of small particles, <20 nm in diameter, into sizes above 50 nm. Aerosol growth was correlated with the presence of organic species, trimethylamine, and MSA in particles ~80 nm and larger, where the organics were similar to those previously observed in marine settings. The organic-rich aerosol contributed significantly to particles active as cloud condensation nuclei (CCN, supersaturation = 0.6%). Our results highlight the potential importance of secondary organic aerosol formation and its role in growing nucleation mode aerosol into CCN-active sizes in this remote marine environment.