On the potential contribution of open lead particle emissions to the central Arctic aerosol concentration
- ISSN: 1680-7324
- DOI: 10.5194/acpd-10-24961-2010
We present direct eddy covariance measurements of aerosol number fluxes,\ndominated by sub-50 nm particles, at the edge of an ice floe drifting in\nthe central Arctic Ocean. The measurements were made during the\nice-breaker borne ASCOS (Arctic Summer Cloud Ocean Study) expedition in\nAugust 2008 between 2 degrees-10 degrees W longitude and 87 degrees-87.5\ndegrees N latitude. The median aerosol transfer velocities over\ndifferent surface types (open water leads, ice ridges, snow and ice\nsurfaces) ranged from 0.27 to 0.68 mm s(-1) during deposition-dominated\nepisodes. Emission periods were observed more frequently over the open\nlead, while the snow behaved primarily as a deposition surface. Directly\nmeasured aerosol fluxes were compared with particle deposition\nparameterizations in order to estimate the emission flux from the\nobserved net aerosol flux. Finally, the contribution of the open lead\nparticle source to atmospheric variations in particle number\nconcentration was evaluated and compared with the observed temporal\nevolution of particle number. The direct emission of aerosol particles\nfrom the open lead can explain only 5-10% of the observed particle\nnumber variation in the mixing layer close to the surface.