AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Size-Resolved Measurements of Ice Nucleating Particles at North American and European Sites
RYAN H. MASON, Meng Si, Cédric Chou, Victoria Irish, Robin Dickie, Pablo Elizondo, Rachel Wong, Miranda Brintnell, Michael Elsassar, Walfried Lassar, Kyle Pierce, Kaitlyn J. Suski, Jonathan Abbatt, Paul DeMott, Thomas Hill, J. Alex Huffman, W. Richard Leaitch, Annie-Marie Macdonald, Andrew Platt, Roland Sarda-Esteve, Corinne L. Schiller, Desiree Toom-Sauntry, Allan Bertram, University of British Columbia
Abstract Number: 216 Working Group: Aerosols, Clouds, and Climate
Abstract Ice nucleating particles (INPs) are a small fraction of the total aerosol population capable of catalyzing ice formation under atmospheric conditions. The formation, albedo, and lifetime of mixed-phase and cirrus clouds may be influenced by the presence of such particles. Compared to ambient measurements of the total number concentration of INPs, relatively little data exists on the size distribution of INPs in the atmosphere. This size information may be useful in source identification, modeling the transport of INPs in the atmosphere, and for determining if common instrumentation captures the majority of the atmospheric INP population. Measured using the micro-orifice uniform deposit impactor-droplet freezing technique (MOUDI-DFT), we report immersion-mode INP number concentrations as a function of particle size at several ground-level sites across North America and Europe, including Arctic, alpine, coastal, marine, agricultural, and suburban environments. More than 91 % of INPs active at -15 °C were found to be supermicron in size and 62 % were in the coarse mode (> 2.5 µm). While these percentages decreased with decreasing temperature, supermicron INPs remained important with nearly half of those active at -25 °C belonging to the coarse mode.