|
Atmos. Chem. Phys., 11, 10619-10636, 2011
www.atmos-chem-phys.net/11/10619/2011/ doi:10.5194/acp-11-10619-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
Aerosol composition and sources in the central Arctic Ocean during ASCOS
1Department of Chemistry, University of Toronto, Toronto, Canada
2Department of Meteorology, Stockholm University, Stockholm, Sweden
3Institute for Ion Physics and Applied Physics, Innsbruck University, Innsbruck, Austria
4Finnish Meteorological Institute, Helsinki, Finland
5Norwegian Institute for Air Research (NILU), Kjeller, Norway
6Sierra Nevada Research Institute, University of California, Merced, Merced, USA
7Science and Technology Branch, Environment Canada, Downsview, Canada
8Bert Bolin Center for Climate Research, Stockholm University, Stockholm, Sweden
*now at: Chemical Sciences Division, National Oceanic and Atmospheric Administration and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, USA
**now at: Institute on Catalysis and Envrionmental Research, University of Lyon, Lyon, France
Abstract. Measurements of submicron aerosol chemical composition were made over the central Arctic Ocean from 5 August to 8 September 2008 as a part of the Arctic Summer Cloud Ocean Study (ASCOS) using an aerosol mass spectrometer (AMS). The median levels of sulphate and organics for the entire study were 0.051 and 0.055 μ g m−3, respectively. Positive matrix factorisation was performed on the entire mass spectral time series and this enabled marine biogenic and continental sources of particles to be separated. These factors accounted for 33% and 36% of the sampled ambient aerosol mass, respectively, and they were both predominantly composed of sulphate, with 47% of the sulphate apportioned to marine biogenic sources and 48% to continental sources, by mass. Within the marine biogenic factor, the ratio of methane sulphonate to sulphate was 0.25 ± 0.02, consistent with values reported in the literature. The organic component of the continental factor was more oxidised than that of the marine biogenic factor, suggesting that it had a longer photochemical lifetime than the organics in the marine biogenic factor. The remaining ambient aerosol mass was apportioned to an organic-rich factor that could have arisen from a combination of marine and continental sources. In particular, given that the factor does not correlate with common tracers of continental influence, we cannot rule out that the organic factor arises from a primary marine source.
Citation: Chang, R. Y.-W., Leck, C., Graus, M., Müller, M., Paatero, J., Burkhart, J. F., Stohl, A., Orr, L. H., Hayden, K., Li, S.-M., Hansel, A., Tjernström, M., Leaitch, W. R., and Abbatt, J. P. D.: Aerosol composition and sources in the central Arctic Ocean during ASCOS, Atmos. Chem. Phys., 11, 10619-10636, doi:10.5194/acp-11-10619-2011, 2011.