1. Motivation and Plans for Natural Source studies in 2014

2. Above, Sjostedt et al, JGR, 2012 found evidence for uptake to acetone to the ocean based on an anti-correlation with DMS measured in the Resolute Bay area from the Amundsen. On the same cruise and in the same area, Chang et al., JGR, 2011 found evidence for nucleation events positively correlated with DMS.

3. Organic carbon is a significant component of the fine particle aerosol in at least the spring and summer R.Y.-W. Chang, C. Leck, M. Graus, M. Muller, J. Paatero, J.F. Burkhart, A. Stohl, L.H. Orr, K. Hayden, S.- M. Li, A. Hansel, M. Tjernstr¨om, W.R. Leaitch, and J.P.D. Abbatt – ACPD, 2011: Aerosol composition and sources in the central Arctic Ocean during ASCOS. Chang et al found Sulphate was about 50:50 marine and continental, and that the marine organic was less oxidized than continental OM. At Alert, the OM is dominated by m/z44, suggesting it is highly oxidized.

4. Alert 4 Evidence for new particle formation associated with clean conditions and MSA is found in observations at Alert during the summertime. Evidence for particle growth also appears for the same conditions, but not necessarily at the same time. Evidence for new particle formation also seen during the PAMARCMIP 2012 flights in clean air coming off Greenland. (J. Burkart)

5. Plans related to Natural Sources for 2014 flights Look for evidence of new particle formation, associated with DMS, and growth near the surface and aloft, and try to associate with source regions. Work to be conducted in region downwind of marginal ice zone (MIZ) coordinated with the Amundsen as well as based on vertical profiles in the Resolute Bay area. Particles smaller than 100 nm difficult to chemically characterize. Some chemical information to be obtained from characterization of sub-100 nm particles based on CCN activity. Look for evidence of primary particle emissions in the fine and ultrafine size range (sea salt; organics; polymer gels(?)), based on size distribution, chemical composition and CCN activity downwind of MIZ. Conduct vertical profiles in order to characterize the depth of the mixed layer and strength of influence of regional natural sources. If liquid cloud is present, profile sampling for cloud droplet number concentrations and liquid water content will be done. Samples will be collected for IN analysis (Bertram).