Observations of Atmospheric Chemical Deposition to High Arctic
Katrina M. Macdonald1, Sangeeta Sharma2, Desiree Toom2, Alina Chivulescu2, Sarah Hanna2, Allan Bertram2, Andrew Platt2, Mike Elsasser2, Lin Huang2, Nathan Chellman3, Joseph R. McConnell3, Heiko Bozem4, Daniel Kunkel4, Ying Duan Lei1, Greg J. Evans1, and Jonathan P. D. Abbatt51Department of Chemical Engineering and Applied Chemistry, University of Toronto, M5S 3E5, Canada 2Climate Research Division, Environment and Climate Change Canada, Toronto, M3H 5T4, Canada 3Desert Research Institute, Reno, 89512, Unites States of America 4Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Becher Weg, 21 55128, Germany 5Department of Chemistry, University of Toronto, M5S 3H6, Canada
Received: 23 Oct 2016 – Accepted for review: 28 Oct 2016 – Discussion started: 07 Nov 2016
Abstract. Rapidly rising temperatures and loss of snow and ice cover have demonstrated the unique vulnerability of the high Arctic to climate change. There are major uncertainties in modelling the chemical depositional and scavenging processes of Arctic snow. To that end, fresh snow samples collected on average every four days at Alert, Nunavut, from September 2014 to June 2015 were analyzed for black carbon, major ions, and metals, and their concentrations and fluxes reported. Comparison with simultaneous measurements of atmospheric aerosol mass loadings yields effective deposition velocities which encompass all processes by which the atmospheric species are transferred to the snow. It is inferred from these values that dry deposition is the dominant removal mechanism for several compounds over the winter while wet deposition increased in importance in the fall and spring, probably due to enhanced scavenging by mixed-phase clouds. Black carbon aerosol was the least efficiently deposited species to the snow. These measurements are a unique data set for comparison to models that incorporate deposition to high Arctic snow.
Macdonald, K. M., Sharma, S., Toom, D., Chivulescu, A., Hanna, S., Bertram, A., Platt, A., Elsasser, M., Huang, L., Chellman, N., McConnell, J. R., Bozem, H., Kunkel, D., Lei, Y. D., Evans, G. J., and Abbatt, J. P. D.: Observations of Atmospheric Chemical Deposition to High Arctic
Snow, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-944, in review, 2016.