Vom Labor ins Feld: Untersuchungen zum Immersionsgefrieren von atmosphärenrelevanten Eisnukleationskeimen
Zusammenfassung der Projektergebnisse
Both project phases of PR6 within INUIT were highly successful. Using LACIS, the Leipzig-Aerosol- Cloud-Interaction-Simulator, new insights were gained into ice nucleation by different atmospherically relevant aerosol particles types. Also, some new measurement techniques were developed, with the most important ones being two types of cold-stages that now supplement the range of instruments to measure immersion freezing available at the TROPOS cloud group. Intensive co-operation took place both with partners from within INUIT and external partners, typically grouped around LACIS measurements. These co-operations included five joint measurements efforts with one other project partner and four large campaigns at LACIS with a number of different project partners participating. Publications from this project were among the forefront to report the following scientific results: inter-comparisons between immersion freezing measured with LACIS and with other instruments in four separate campaigns and additionally with the new immersion freezing measurement devices at TROPOS all showed that LACIS gives reliable results; altogether, these inter-comparisons helped to understand the reliability of the suite of different available measurement techniques that exist in the community today; ice nucleation activity of mineral dust particles depends on their size; K-feldspar is the most ice active mineral dust among a large range examined, and weathering reduces its ice activity to that of feldspar-free clay, hence the fraction of K-feldspar contained in mineral dust particles may give an indication of the particles ice activity; ice activity of biogenic ice nucleators (bacteria, pollen, fungal spores) always traces back to biogenic macromolecules, which typically induce ice nucleation at higher temperatures than mineral dust particles; the size of a biogenic macromolecule influences the temperature at which it induces ice nucleation; particles that are a mixture of a biogenic macromolecule and a mineral dust particle induce ice nucleation similar to the pure biogenic particle; for ash particles, the determined ice activity depends largely on the particle generation method (dry dispersion versus generation from a suspension) so that the measurement method will largely influence the obtained result, and CaSO4 and CaO contained in coal fly ash particles from power plants likely is responsible for the ice activity observed for these particles; at least some ice nucleation observed for conditions below 100% relative humidity (wrt. water) can be described as immersion freezing when accounting for a freezing point depression; time dependence of the ice nucleation process can well be described with CNT (Classical Nucleation Theory) and assuming a contact angle distribution, however, temperature plays a larger role for the nucleation process than time; ice nucleation observed in river water originated from the biosphere in the river’s watershed; anthropogenic pollution in Beijing did not contribute to the observed atmospheric ice nucleating particles. Besides for these results, parameterizations of measurements are provided in a number of the publications, often given for both time dependent and time independent approaches, additionally adding to the contributions from RP6 to the field of ice nucleation.
Projektbezogene Publikationen (Auswahl)
- (2013), Immersion freezing of birch pollen washing water, Atmos. Chem. Phys., 13, 10989–11003
Augustin, S., H. Wex, D. Niedermeier, B. Pummer, H. Grothe, S. Hartmann, L. Tomsche, T. Clauss, J. Voigtländer, K. Ignatius, and F. Stratmann
(Siehe online unter https://doi.org/10.5194/acp-13-10989-2013) - (2013), Immersion freezing of ice nucleating active protein complexes, Atmos. Chem. Phys., 13, 5751-5766
Hartmann, S., S. Augustin, T. Clauss, H. Wex, T. Santl Temkiv, J. Voigtländer, D. Niedermeier, and F. Stratmann
(Siehe online unter https://doi.org/10.5194/acp-13-5751-2013) - (2014), Kaolinite particles as ice nuclei: learning from the use of different kaolinite samples and different coatings, Atmos. Chem. Phys., 14, 5529-5546
Wex, H., P. J. DeMott, Y. Tobo, S. Hartmann, M. Rösch, T. Clauss, L. Tomsche, D. Niedermeier, and F. Stratmann
(Siehe online unter https://doi.org/10.5194/acp-14-5529-2014) - (2014), The immersion mode ice nucleation behavior of mineral dusts: A comparison of different pure and surface modified dusts, Geophys. Res. Lett., 41
Augustin-Bauditz, S., H. Wex, S. Kanter, M. Ebert, F. Stolz, A. Prager, D. Niedermeier, and F. Stratmann
(Siehe online unter https://doi.org/10.1002/2014GL061317) - (2015), Ice nucleation by water-soluble macromolecules, Atmos. Chem. Phys., 15, 4077–4091
Pummer , B. G., C. Budke, S. Augustin-Bauditz, D. Niedermeier, L. Felgitsch, C. J. Kampf, R. G. Huber, K. R. Liedl, T. Loerting, T. Moschen, M. Schauperl, M. Tollinger, C. E. Morris, H. Wex, H. Grothe, U. Pöschl, T. Koop, and J. Fröhlich-Nowoisky
(Siehe online unter https://doi.org/10.5194/acp-15-4077-2015) - (2015), Intercomparing different devices for the investigation of ice nucleating particles using Snomax as test substance, Atmos. Chem. Phys., 15, 1463-1485
Wex , H., S. Augustin-Bauditz, Y. Boose, C. Budke, J. Curtius, K. Diehl, A. Dreyer, F. Frank, S. Hartmann, N. Hiranuma, E. Jantsch, Z. A. Kanji, A. Kiselev, T. Koop, O. Moehler, D. Niedermeier, B. Nillius, M. Roesch, D. Rose, C. Schmidt, I. Steinke, and F. Stratmann
(Siehe online unter https://doi.org/10.5194/acp-15-1463-2015) - (2016), 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
Augustin-Bauditz, S., H. Wex, C. Denjean, S. Hartmann, J. Schneider, S. Schmidt, M. Ebert, and F. Stratmann
(Siehe online unter https://doi.org/10.5194/acp-16-5531-2016) - (2017), Leipzig Ice Nucleation chamber Comparison (LINC): Intercomparison of four online ice nucleation counters, Atmos. Chem. Phys., 17, 11683 - 11705
Burkert-Kohn, M., H. Wex, A. Welti, S. Hartmann, S. Grawe, L. Hellner, P. Herenz, J. D. Atkinson, F. Stratmann, and Z. A. Kanji
(Siehe online unter https://doi.org/10.5194/acp-17-11683-2017) - (2018), Coal fly ash: Linking immersion freezing behavior and physico-chemical particle properties, Atmos. Chem. Phys., 18, 13903–13923
Grawe, S., S. Augustin-Bauditz, H.-C. Clemen, M. Ebert, S. Eriksen Hammer, J. Lubitz, N. Reicher, Y. Rudich, J. Schneider, R. Staacke, F. Stratmann, A. Welti, and H. Wex
(Siehe online unter https://doi.org/10.5194/acp-18-13903-2018) - (2018), Ice nucleating particle concentrations unaffected by urban air pollution in Beijing, China, Atmos. Chem. Phys., 18, 3523–3539
Chen, J., Z. Wu, S. Augustin-Bauditz, S. Grawe, M. Hartmann, X. Pei, Z. Liu, D. Ji, and H. Wex
(Siehe online unter https://doi.org/10.5194/acp-18-3523-2018)
