Kompositionsanalyse von Eisresiduen mittels der Kombination von Aerosol-Massenspektrometrie mit einem virtuellem Gegenstromimpaktor
Zusammenfassung der Projektergebnisse
In this project, we studied the chemical and microphysical properties of atmospheric ice nucleating particles (INP). Such INP are important for the freezing of cloud droplets at temperatures higher than -38°C, a process that it essential for the formation of rain at mid-latitudes and cloud climate forcing. We used two different approaches: One part focused on real ambient clouds that exist between zero and -38°C, the so-called mixed phase clouds, because ice crystals and supercooled cloud droplets can co-exist in this temperature regime. We studied this kind of clouds at the high Alpine research station Jungfraujoch where we operated a specially designed inlet system (Ice-CVI) that extracts the ice crystals from the mixed-phase clouds, evaporates the ice, and delivers the residual aerosol particles to the connected measurement instruments. The resulting composition measured with an aerosol mass spectrometer partly confirmed previous findings that mineral dust and metal-containing particles are enriched in ice residuals compared to the out-of-cloud aerosol. However, during the field campaign in 2017, we observed also sea-spray containing particles in the residuals, a finding that had not been expected because this particle type is typically not acting as an INP. A speculative explanation may be the presence of biological compound from the sea surface microlayer that initiated the freezing. A problem that occurred during these measurements was the large presence of aluminum oxide particle detected in the residuals by electron microscopy that are thought to are artefact particles generated by the inlet system. On the other hand, since all surfaces of the inlet had been coated with Nickel to avoid such contamination, this issue remains unclear. The second approach was to combine an ice nucleus counter with a pumped CVI in order to extract the ice crystals from the IN counter. An IN counter creates an artificial ice cloud by cooling the sampled air and thereby producing supersaturation with respect to ice, such that the INP contained in the air form ice crystals. By the combination with a pumped CVI that extracts only the ice crystals and leads them to the analysis instruments, the properties of potential INP in ambient air can be studied, also when no natural cloud is present. This development turned out to be extremely challenging such that we could demonstrate a proof-of-concept only in the last project year. For this, we created a particle mixture consisting of a “good” INP and a “bad” INP with different pre-selected sizes. This mixture was then led through the IN counter and the pumped CVI to the analysis instruments. Both the sizing instrumentation and the chemical composition measurements clearly show that only the “good” INP were found in the residuals when the temperature was above -38°. Only below -38°, where homogeneous freezing occurs, the “bad” INP was also observed in the residuals. Since the success of this development was achieved so late in the project phase, no field experiments with this combination could be conducted. However, the technology and the expertise is now available and can be used for further INP studies.
Projektbezogene Publikationen (Auswahl)
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Single-particle characterization of ice-nucleating particles and ice particle residuals sampled by three different techniques, Atmos. Chem. Phys., 15, 4161-4178, 2015
Worringen, A., Kandler, K., Benker, N., Dirsch, T., Mertes, S., Schenk, L., Kästner, U., Frank, F., Nillius, B., Bundke, U., Rose, D., Curtius, J., Kupiszewski, P., Weingartner, E., Vochezer, P., Schneider, J., Schmidt, S., Weinbruch, S., and Ebert, M.
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The Ice Selective Inlet: a novel technique for exclusive extraction of pristine ice crystals in mixed-phase clouds, Atmospheric Measurement Techniques, 8, 3087- 3106, 2015
Kupiszewski, P., Weingartner, E., Vochezer, P., Schnaiter, M., Bigi, A., Gysel, M., Rosati, B., Toprak, E., Mertes, S., and Baltensperger, U.
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An Overview on the INUIT-BACCHUS-ACTRIS Field Experiment in Cyprus in April 2016, Joint ACTRIS-BACCHUS-ChArMEx International workshop "Atmospheric Processes in the Mediterranean (APM 2016)", Larnaca, Cyprus, 17-21 Oct. 2016
Schneider, J., et al.
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Ice residual properties in mixed-phase clouds at the highalpine Jungfraujoch site, J. Geophys. Res. Atmos., 121, 12343–12362, 2016
Kupiszewski, P., M. Zanatta, S. Mertes, P. Vochezer, G. Lloyd, J. Schneider, L. Schenk, M. Schnaiter, U. Baltensperger, E. Weingartner
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Laboratory-generated mixtures of mineral dust particles with biological substances: characterization of the particle mixing state and immersion freezing behavior, Atmos. Chem. Phys., 16, 5531-5543, 2016
Augustin-Bauditz, S., Wex, H., Denjean, C., Hartmann, S., Schneider, J., Schmidt, S., Ebert, M., and Stratmann, F.
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Chapter 8: Measurements of ice nucleating particles and ice residuals, in Ice Formation and Evolution in Clouds and Precipitation: Measurement and Modeling Challenges, edited, Meteor. Monogr., 2017
Cziczo, D. J., L. A. Ladino Moreno, Y. Boose, Z. A. Kanji, P. Kupiszewski, S. Lance, S. Mertes, and H. Wex
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Online single particle analysis of ice particle residuals from mountain-top mixed-phase clouds using laboratory derived particle type assignment, Atmos. Chem. Phys., 17, 575-594, 2017
Schmidt, S., Schneider, J., Klimach, T., Mertes, S., Schenk, L. P., Kupiszewski, P., Curtius, J., and Borrmann, S.
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Single particle analysis of eastern Mediterranean aerosol particles: Influence of the source region on the chemical composition, Geophysical Research Abstracts Vol. 19, EGU2017-4419, 2017, EGU General Assembly 2017
Clemen, H.-C., Schneider, J., Köllner, F., Klimach, T., Pikridas, M., Stavroulas, I., Sciare, J:, Borrmann, S.
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(2018). Characterization of ice particles residuals from mixed-phase clouds at the high alpine research station Jungfraujoch to infer aerosol properties of ice nucleating particles inside real clouds. 2018 INUIT Final Conference and 2nd Atmospheric Ice Nucleation Conference, Grasellenbach, Germany, 26 February - 1 March 2018
Mertes, S., U. Kästner, J. Schneider, H.-C. Clemen, S. Schmidt, P. Kupiszewski, M. Zanatta and F. Stratmann
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(2018). Experimental operation mode verification of the coupling between ice nuclei counter and a pumped counterflow virtual impactor devised for aerosol property measurements of ice nucleating particles. 2018 INUIT Final Conference and 2nd Atmospheric Ice Nucleation Conference, Grasellenbach, Germany, 26 February - 1 March 2018
Mertes, S., L. Schenk, A. Welti, U. Kästner, R. Kohl, F. Frank, J. Schneider, H. C. Clemen, S. Eriksen Hammer, D. Rose, H. Bingemer, S. Grawe, H. Wex, M. Ebert, J. Curtius and F. Stratmann
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Chemical analysis of ice particle residuals from mixed-phase clouds with the single particle mass spectrometer ALABAMA, INUIT Final Conference, Grasellenbach, Germany, 26 Feb – 01 Mar 2018
Clemen, H.-C., Schneider, J., Eppers, O., Klimach, T., Mertes, S., Kästner, U., Borrmann, S.
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Coal fly ash: linking immersion freezing behavior and physicochemical particle properties, Atmos. Chem. Phys., 18, 13903-13923, 2018
Grawe, S., Augustin-Bauditz, S., Clemen, H.-C., Ebert, M., Eriksen Hammer, S., Lubitz, J., Reicher, N., Rudich, Y., Schneider, J., Staacke, R., Stratmann, F., Welti, A., and Wex, H.
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Composition of ice particle residuals in mixed-phase clouds at Jungfraujoch (Switzerland): enrichment and depletion of particle groups relative to total aerosol, Atmos. Chem. Phys., 18, 13987-14003, 2018
Eriksen Hammer, S., Mertes, S., Schneider, J., Ebert, M., Kandler, K., and Weinbruch, S.
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Measurements of ice nucleation particles and ice residuals from mixed phase clouds at the High Alpine Research Station Jungfraujoch – What have we learned from the INUIT experiments?, INUIT Final Conference, Grasellenbach, Germany, 26 Feb – 01 Mar 2018
Schneider, J., and the INUIT-JFJ Team
