Ice Nuclei Research
Cirrus and mixed-phase clouds with ice play a key role in the formation of rain. But we still don’t know what makes a good ice nuclei. The GCVI and other devices (PCVI, HTDMA), are revealing the detailed properties of ice nuclei.
A unique deployment of the PCVI involves coupling it to a new ice nucleation chamber as well as a cloud condensation nucleus counter CCN (see Hiranuma et al. (2011) AMTD reference). Ice nuclei, particles that can form ice crystals in cirrus and other cold-temperature clouds, are poorly understood in our atmosphere but have important climate impacts. Tools like the PCVI allow careful studies of particle ice nucleating properties as a function of particle size.
The SEMS is used in ice nuclei research to prepare aerosol for cloud chamber experiments. The ability of the SEMS to separate particles based on mobility allows users to remove one of the key variables in the atmosphere – particle size – out of the equation. When particles are ‘activated’ into droplets or ice crystals the results are more easily interpreted as due to composition or morphology when experiments are performed on single-sized populations. Starting at one particle size greatly reduces the uncertainty of eliminating particle volume or surface area effects.