Competition between Local and Distant Sources Determining the Concentration of Warm Temperature Ice Nucleating Particles in the Boundary Layer

Thomas C. J. Hill, SONIA KREIDENWEIS, Russell Perkins, Claudia Mignani, Leah Grant, Jessie Creamean, Paul DeMott, Carson Hume, Marina Nieto-Caballero, Kevin R. Barry, Noelle Bryan, Elizabeth Stone, Brian Heffernan, Teresa Feldman, Chamari Mampage, Janeshta Fernando, Drew Juergensen, Colorado State University

     Abstract Number: 688
     Working Group: Bioaerosols

Abstract
We still know relatively little about the relative contributions of local versus distant sources of ice nucleating particles (INPs) to the boundary layer. INPs active warmer than -20°C are of particular interest due to their relevance to mixed phase cloud glaciation and their predominantly organic/biological composition owing to their plant and/or soil sources. Here, we highlight results from several recent and complementary field campaigns that have shed light on factors that control the relative contributions of local versus distant sources of INPs. This included co-located measurements from the BioAerosols and Convective Storms (BACS) and Biology integration institute: Regional OneHealth Aerobiome Discovery Network (BROADN) campaigns in the northern Colorado plains, and measurements from Tracking Aerosol Convection Interactions ExpeRiment (TRACER) near Houston, Texas. During TRACER, the similarity of INP spectra at two sites 76 km apart indicated that INP concentration and composition was frequently dominated by regional transports. Similarly, results from a BROADN/BACS intensive suggest that exceptionally high concentrations of warm-temperature INPs (~1 L^-1 at -10°C) resulted from emissions driven by thunderstorms in mesoscale convective systems 50-150 km upwind from the sampling site. In the absence of specific local disturbances (strong rain/hail, winds that raise soil dust, harvesting, plowing, fire) warm-temperature INPs will be an integration of regional sources.