Composition analysis of ice particle residuals combining aerosol mass spectrometry and counterflow virtualimpactor technique

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This renewal proposal of an ongoing research project within the research unit INUIT (Ice Nuclei research UnIT) aims for the physico-chemical characterization of ambient ice nucleating particles (INP) and ice particle residuals (IPR). Two major experimental techniques will be deployed: counterflow virtual impactor (CVI) technique and laser ablation aerosol mass spectrometry. INP in ambient aerosol will be activated by an IN counter and the ice crystals will be extracted and evaporated by a pumped CVI system that was developed in the first phase of INUIT. The released IN particles will be analyzed by the aerosol mass spectrometer. This experiment will be carried out during a field campaign in proximity to sources of potential ice nucleating particles (mineral dust, bioparticles, anthropogenic pollution particles). An appropriate location is the Mediterranean region, e.g. southern Spain. IPR will be sampled directly from mixed phase clouds by a specially designed Ice-CVI that extracts only ice crystals and rejects the supercooled droplets. The ice is evaporated in the dry counterflow and the residual particles will be analyzed by the aerosol mass spectrometer. This experiment will be conducted on a mountain station (Jungfraujoch). The combination of IN counter, pumped CVI and aerosol mass spectrometer will also be applied under laboratory conditions for the investigation of the ice nucleation behavior of external and internal particle mixtures (e.g., biologicalmineral). The single particle aeLosol mass spectrometer will also be used for the characterization of the mixing state of the laboratory-generated particle mixtures.