AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Observations of Fluorescent Aerosol and Ice Nucleating Particle Concentrations during Wintertime at a Pacific Coastal Site
MARKUS PETTERS, Hans Taylor, Thomas Hill, Paul DeMott, Samuel Atwood, Christina S. McCluskey, Sonia Kreidenweis, Nicholas Rothfuss, Kimberly Prather, Gavin Cornwell, Andrew Martin, North Carolina State University
Abstract Number: 308 Working Group: Bioaerosols
Abstract We report observations of the aerosol characteristics observed at Bodega Bay Marine Laboratory between January and March 2015. These include size- and supersaturation resolved cloud condensation nuclei (CCN), ice nucleating particles (INPs) measured from aerosol-into-liquid and aerosol-filter sampling, as well as fluorescent particles measured with an optical particle counter (WIBS-4A). The directly measured CCN supersaturation spectrum could be predicted based on the aerosol size distribution and the associated measured kappa values. INP concentrations were determined using two different cold-stage methods that differed by particle collection technique, drop volume, and cold-stage implementation. Results from these techniques are intercompared against an online technique. Technical details associated with sample handling required for cold-stage measurement of ambient INP concentrations are discussed. The fluorescent particle concentration followed a regular diel cycle. Two multi-day time periods with enhanced fluorescent particle concentration following mesoscale precipitation events were observed. Fluorescent particles were grouped together by characteristic excitation–emission profiles. INP concentrations at T > -20 degree C from both instruments correlated well with two of these groupings. These data add to an emerging body of literature that suggests the presence of a significant terrestrial biological source for warm INPs.