Ice Nucleation Measurements using PNNL mobile ice chamber from FIN-2 Workshop

 
Poster PDF

Author

Gourihar Kulkarni — Pacific Northwest National Laboratory

Category

Microphysics (cloud, aerosol and/or precipitation)

Description

Ice clouds constitute the largest source of uncertainty in predicting the Earths’ climate behavior. The uncertainty arises in part because of the lack of understanding of the complex ways in which these clouds are formed. At temperatures warmer than −38 C ice formation take place heterogeneously. Heterogeneous ice nucleation requires special atmospheric aerosols called ice nucleating particles (INP) that lower the free energy barrier for the nucleation and, depending upon different INP surface characteristics (e.g., size and morphology, solubility, epitaxial and active site distribution), determine the ice nucleation efficiency. INP efficiencies are measured using an ice nucleation chamber, and there are different chamber designs. In order to understand the sensitivity of these chamber designs towards INP measurements, a Fifth International Ice Nucleation (FIN) – 2 workshop was organized at the AIDA facility during March, 2015. PNNL's mobile ice nucleation chamber was also deployed at the AIDA facility. In this meeting chamber results from this campaign and also results that demonstrate the unique features, such as immersion freezing spectra from -15 to -40 C under 30 minutes, no droplet breakthrough artifacts, flexibility to investigate both deposition and immersion mechanisms, and adaptability to separate ice residuals, will be presented.