Date of Award
Master of Science (MS)
Chemistry & Biochemistry
Margaret A. Tolbert
Mineral dust particles are efficient ice nuclei (IN). NX illite, a new atmospheric dust surrogate, has been suggested to better represent atmospheric dust. Here Raman microscopy is used to examine the ice-nucleating efficiency of NX illite, NX illite coated with a five dicarboxylic acid mixture (M5), and pure M5. It was found that NX illite is a good IN, Sice=1.07 ± 0.01 at -47°C, with a slight Sice increase at lower temperatures, while pure M5 is a poor IN, Sice=1.30 ± 0.02 at -40°C, and relatively temperature independent. However, M5 shows different ice crystal mechanisms at low and high temperatures, suggesting depositional nucleation at low temperatures and immersion nucleation at high temperatures. In addition, 1:1 NX illite:M5 w/w is the threshold composition for hindering NX Illite's ice-nucleating ability. Understanding laboratory surrogates of atmospheric dust will lead to a more complete understanding of ice cloud formation and their effect on climate.
Primm, Katherine Marie, "Depositional Ice Nucleation on NX illite and Mixtures of NX illite with Organic Acids" (2014). Chemistry & Biochemistry Graduate Theses & Dissertations. 142.