J. Li1, R. H. Mason2, M. Si2, L. A. Ladino3, J. Yakobi-Hancock3, J. P. D. Abbatt3, A. K. Bertram2, J. A. Huffman1 1Department of Chemistry and Biochemistry, University of Denver, USA 2Department of Chemistry, University of British Columbia, Canada 3Department of Chemistry, University of Toronto, Canada Classes of biological particles have been shown to be particularly efficient atmospheric ice nuclei (IN) and thus may influence mixed-phase cloud formation and evolution in certain regions of the globe. Recent studies in terrestrial environments have shown that biological particles correlate well with IN, especially during rain and fog events. Marine environments have been relatively under-studied, despite their dominance of the global surface. Models have also recently suggested that marine zones with high levels of chlorophyll content are likely to provide increased production of biological IN. During the August 2013 a set of intensive measurements were conducted from a mobile trailer located 20 m from the west coast of Vancouver Island, British Columbia and 2 km from the small town of Ucluelet. The experiments were conducted as part of a campaign to examine cloud formation properties of marine aerosol, as one component of NETCARE (the NETwork on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) project. A full suite of aerosol instrumentation was operated for approximately one month. Key instruments utilized for this presentation include the wideband integrated bioaerosol sensor (WIBS 4A) and the multiple orifice uniform deposition impactor (MOUDI) coupled with an off-line droplet freezing apparatus (DFA) for the measurement of ice nucleation activity of particles in immersion mode. The WIBS provides a proxy for airborne biological particle content by detecting fluorescence in one of three emission bands. Particles shown to be fluorescent by the WIBS instrument here were divided into seven categories based on which of three fluorescent channels showed signal above baseline. Hierarchical agglomerative cluster analysis was also performed on the WIBS data to determine if unique groups of fluorescent particles could be differentiated. Results of certain sub-groups within both WIBS category and cluster analyses are shown to correlate positively with IN number concentration, and micrographs of high bioparticle concentrations collected via impaction suggest that IN in the rural region are influenced by bioparticles.

Linking airborne biological particles and ice nuclei in a rural, marine environment near Ucluelet, British Columbia

249th National Meeting (2015)

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