A pumped counterflow virtual impactor (PCVI) was set up to separate ice nucleating particle (INP) counter produced ice particles that had been activated to ice from non-activated aerosol particles. The released INP were characterized with regard to their physico-chemical properties. A successful separation (PCVI) of INP for water-subsaturated conditions is proven. First results of INP properties are presented which were gained during a campaign at the high altitude research station Jungfraujoch.
A pumped counterflow virtual impactor (PCVI) was set up to separate ice nucleating particle...
Received: 11 Sep 2014 – Accepted for review: 26 Sep 2014 – Discussion started: 21 Oct 2014
Abstract. A specific instrument combination was developed to achieve a better microphysical and chemical characterization of atmospheric aerosol particles that have the potential to act as ice nucleating particles (INP). For this purpose a pumped counterflow virtual impactor system called IN-PCVI was set up and characterized to separate ice particles that had been activated on INP in the Fast Ice Nucleus Chamber (FINCH) from interstitial, non-activated particles. This coupled setup consisting of FINCH (ice particle activation and counting), IN-PCVI (INP separation and preparation), and further aerosol instrumentation (INP characterization) had been developed for the application in field experiments. The separated INP were characterized on-line with regard to their total number concentration, number size distribution and chemical composition, especially with the Aircraft-based Laser Ablation Aerosol Mass Spectrometer ALABAMA. Moreover, impactor samples for electron microscopy were taken. Due to the coupling the IN-PCVI had to be operated with different flow settings than known from literature, which required a further characterization of its cut-off-behavior. Taking the changed cut-off-behavior into account, the INP number concentration measured by the IN-PCVI system was in good agreement with the one detected by the FINCH optics for water saturation ratios up to 1.01 (ice saturation ratios between 1.21–1.34 and temperatures between −18 and −26 °C). First field results of INP properties are presented which were gained during the INUIT-JFJ/CLACE 2013 campaign at the high altitude research station Jungfraujoch in the Bernese Alps, Switzerland (3580 m a.s.l.).
A pumped counterflow virtual impactor (PCVI) was set up to separate ice nucleating particle (INP) counter produced ice particles that had been activated to ice from non-activated aerosol particles. The released INP were characterized with regard to their physico-chemical properties. A successful separation (PCVI) of INP for water-subsaturated conditions is proven. First results of INP properties are presented which were gained during a campaign at the high altitude research station Jungfraujoch.
A pumped counterflow virtual impactor (PCVI) was set up to separate ice nucleating particle...