10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Nanoscale Ice-Nucleating Particles in Waterbodies in an Agricultural Area
HEIKE WEX, Kathryn A. Knackstedt, Bruce Moffett, Susan Hartmann, Janine Fröhlich-Nowoisky, Thomas Hill, Sarah Grawe, Robert Michael McKay, Institute for Tropospheric Research, Germany
Abstract Number: 775 Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds
Abstract Ice nucleating particles (INPs) are a neglected, but integral component of the water cycle. Abundant INPs were identified from surface waters of both the Maumee River and Lake Erie with freezing profiles spanning a temperature range tested from -30°C to -20°C. River INPs were largely attributed to biogenic macromolecules, based on their characterization showing heat denaturation of ice activity and size-fractionation of the activity using a 0.2 μm membrane. Higher concentrations of INPs were found in river samples compared to lake samples. However, the latter showed a broader increase in the freezing profile, pointing towards a different population of INPs being present in the lake.
Seasonal analysis of INPs that were ice active ≥ -10°C (INP-10) showed their concentration to correlate with river discharge, suggesting a watershed origin of these INPs, a characterization supported by analysis showing similar ice nucleating signatures derived from the river and the soil fungus Mortierella alpina suggesting that fungal INPs may dominate the INP population of the river. Aerosols derived from turbulence features in the river can include INP-10 that may potentially influence regional weather. INP-10 contained within aerosols generated from a weir spanning the river ranged in concentration from 1-11 INP m-3 which represented a fold-change of 3.2 over average INP-10 concentrations sampled from aerosols at control locations.