10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Ice Nucleation Activity of Glassy Soil Organic Particles under Cirrus Conditions
SWARUP CHINA, Daniel Veghte, Joseph Charnawskas, Johannes Weis, Kaitlyn J. Suski, Gourihar Kulkarni, Bingbing Wang, Peng Lin, Alla Zelenyuk, Mary Gilles, Daniel Knopf, Alexander Laskin, Pacific Northwest National Laboratory
Abstract Number: 1013 Working Group: Unraveling the Many Facets of Ice Nucleating Particles and Their Interactions with Clouds
Abstract Glassy soil organic particles can play a significant role in heterogeneous ice nucleation under cirrus cloud conditions. Our previous study showed formation of airborne soil organic particles (ASOP) from the soil surface after intensive rain events in the Southern Great Plains (SGP), Oklahoma. In this study we collected aliquots of ‘soil organic matter brine’ from a puddle created by the rain events to generate spherical solid ASOP-like particles under laboratory conditions. Chemical imaging and micro-spectroscopy analysis of soil organic particles are performed to characterize their physico-chemical properties. Furthermore, molecular characterization and elemental composition analysis of particle constituents are performed by high-resolution mass spectrometry. We utilize a custom-built ice nucleation cell, interfaced with an Environmental Scanning Electron Microscope (IN-ESEM platform) operated at temperature and relative humidity relevant for cirrus cloud formation to investigate ice nucleation propensity of these laboratory generated soil organic particles. We show dynamic microscopic observations of ice nucleation events on individual submicron size soil organic particles via deposition mode. Our results show that relative humidity with respect to ice of soil organic particles is similar for to that of Suwannee River Fulvic Acid particles. Overall, our results show that soil organic particles promote ice formation under cirrus conditions.