Date of Award


Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Atmospheric Sciences (PhD)

Administrative Home Department

Department of Physics

Advisor 1

Will Cantrell

Committee Member 1

Raymond Shaw

Committee Member 2

Jennifer Becker

Committee Member 3

Alexander Kostinski

Committee Member 4

Lynn Mazzoleni


We present results from experiments that emulate atmospheric ice nucleation by aerosols. We have refined experimental techniques to improve measurements of ice forming nuclei in the contact mode. Our results show that atmospherically relevant dusts such as kaolinite, feldspar, rhyolitic ash, and Arizona Test Dust have efficiencies in the contact mode that are higher than the immersion mode. Experiments with bacteria show that biological material has the potential to contribute significantly to ice concentrations, but has large variability. By choosing a soluble compound as an ice nucleus, we are able to place bounds on the timescale for contact freezing and estimate the nucleation time from impact to be 10−9 seconds. Finally, we conclude that the contact mode can increase nucleation rates in two ways: by the creation of a triple-phase line with an insoluble nucleus, or by the collision event.