Biogenic Contributions to Summertime Arctic Aerosol: Observations of Aerosol Composition from the Netcare 2014 Aircraft Campaign

Thursday, 18 December 2014
Megan D Willis1, Julia Burkart1, Franziska Koellner2, Johannes Schneider3, Heiko Bozem2, Peter Michael Hoor4, Ralf Brauner5, Andreas Bodo Herber6, Warren Richard Leaitch7 and Jonathan Abbatt1, (1)University of Toronto, Department of Chemistry, Toronto, ON, Canada, (2)Johannes Gutenberg University of Mainz, Institute for Atmospheric Physics, Mainz, Germany, (3)Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany, (4)Johannes Gutenberg University of Mainz, Mainz, Germany, (5)Jade University of Applied Sciences, Department of Maritime Studies, Elsfleth, Germany, (6)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (7)Environment Canada, Toronto, ON, Canada
The Arctic is a complex and poorly studied aerosol environment, impacted by strong anthropogenic contributions during winter months and by regional sources in cleaner summer months. In order to gain a predictive understanding of the changing climate in this region, it is necessary to understand the balance between these two aerosol sources to clarify how aerosol might be altered by or contribute to climate change. We present results of vertically resolved, submicron aerosol composition from an Aerodyne high-resolution aerosol mass spectrometer (AMS) during the NETCARE 2014 Polar6 aircraft campaign. The campaign was based in the high Arctic, at Resolute, NU (74°N), allowing measurements from 60 to 2900 meters over ice, open water and near the ice-edge. Concurrent measurements aboard the Polar6 included ultrafine and accumulation mode particle number and size, cloud condensation nuclei concentrations, trace gas concentrations and single particle composition. Aerosol vertical profiles measured by the AMS can be broadly characterized into two regimes corresponding to different meteorological conditions: the first with very low aerosol loading (<0.1 μg/m3) at low altitudes compared to that aloft and high numbers of nucleation mode particles, and the second with higher concentrations at lower levels. This second regime was associated with low concentrations of nucleation mode particles, and higher observable levels of methane sulphonic acid (MSA) from AMS measurements at low altitudes. MSA, produced during the oxidation of dimethyl sulphide, is a marker for the contribution of ocean-derived biogenic sulphur to particulate sulphur and could be identified and quantified using the high-resolution AMS. MSA to sulphate ratios were observed to increase towards lower altitudes, suggesting a contribution to aerosol loading from the ocean. In addition, we present measurements of aerosol neutralization and the characteristics of organic aerosol that relate to the growth of ultrafine particles to accumulation mode sizes.