AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Airborne Observations of Aerosol Composition in the Summertime Arctic
MEGAN WILLIS, Julia Burkart, Jennie L. Thomas, Franziska Kollner, Johannes Schneider, Heiko Bozem, Peter M. Hoor, Amir A. Aliabadi, Hannes Schulz, Andreas Herber, W. Richard Leaitch, Jonathan Abbatt, University of Toronto, Toronto, Canada
Abstract Number: 121 Working Group: Remote and Regional Atmospheric Aerosols
Abstract The Arctic is a complex and poorly understood aerosol environment, impacted by strong anthropogenic contributions during winter to spring, and by regional sources in cleaner summer months. Our understanding of summertime Arctic aerosol and cloud remains incomplete, in part due to a scarcity of measurements focusing on the role of regional sources in shaping aerosol chemical and physical properties. To aid in addressing these uncertainties we made measurements of aerosol physical and chemical properties aboard an aircraft, as part of the NETCARE project, allowing measurements from 60 to 3000 meters over ice and open water. This summertime campaign was based in the Canadian High Arctic, at Resolute, NU (74°N), in a general time period and location that was shown to have high biological activity in the surface ocean. Here, we focus on observations of sub-micron aerosol composition from an aerosol mass spectrometer during two general time periods. First, under stable and regionally influenced atmospheric conditions with relatively low carbon monoxide and black carbon concentrations (< 100 ppbv and < 50 ng/m3, respectively), we observed organic aerosol (OA)-to-sulfate ratios ranging from ~0.5 to greater than 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 sub-micron 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. Second, under less-regionally influenced conditions our study area was impacted by a combination of sources including biomass burning emissions from the North West Territories, bringing higher black carbon and OA concentrations, as well as marine emissions from Hudson and Baffin Bays. With these observations we explore the composition and formation processes contributing to cloud condensation nuclei in the summertime Arctic.