Ice Nucleation Activity and Ice Cloud Processing of Glassy Soil Organic Particles Under Cirrus Conditions

Glassy organic particles can play a significant role in heterogeneous ice nucleation under cirrus conditions. A recent study shows formation of airborne soil organic particles (ASOP) from the soil surface after water droplet impaction, following intensive rain events in the Southern Great Plains (SGP), Oklahoma, and experimental irrigation. In this study we collected ASOP particles at the SGP site during spring 2016. We also collected aliquot of ‘soil organic matter brine’ from a puddle created by the rain events to produce spherical solid ASOP-like particles under laboratory conditions. Chemical imaging and micro-spectroscopy analysis of ASOP are performed to characterize their physico-chemical properties. 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 ASOP. Preliminary data shows that ASOP particles promote ice formation under cirrus conditions. We also investigate the dynamics of sublimation behavior of ice crystals formed by ASOP at nanometer scale and further investigate the processed ASOP particle (i.e. ice cloud processing).