INUIT (Ice Nuclei research UnIT) is a research unit funded by the German National Science (DFG) aiming at the investigation of heterogeneous freezing processes in the atmosphere. Within the research unit, both atmospheric and laboratory measurements are carried out. Based on the measured data, parameterizations for use in atmospheric models are developed and tested in the framework of case studies. INUIT currently is in its second phase of funding. Within INUIT, TROPOS has been and is engaged in two research projects (RPs):
This project is carried out in collaboration between TROPOS and the Max Planck Institute, for Chemistry in Mainz (Johannes Schneider). Goal of this project is the physical and chemical characterization of atmospheric ice nuclei (IN) and small ice particle residuals (IPR). This is achieved by combining a counter flow virtual impactor (CVI, counterflow virtual impactor) with online mass spectroscopy, and measurements of aerosol physical properties such as particle size. Atmospheric ice particle residues sampled from real clouds as well as IN activated by means of an ice nucleus counter are considered.
Goal of this project is the quantification of the immersion freezing behavior of size selected pure, and surface modified ice nucleation particles (INP). As well mineral dusts as biogenic particles are investigated. Additionally, the second project phase has a stronger focus on more atmospherically relevant INP. Furthermore, parameterizations for the description of immersion freezing processes in atmospheric models are developed. The measurements are carried out at LACIS (Leipzig Aerosol Cloud Interaction Simulator).
TROPOS results achieved in the framework of INUIT can be found in:
Augustin et al. (2013), Immersion freezing of birch pollen washing water, Aerosol Chem. Phys., 13, 10989–11003.
Augustin-Bauditz et al. (2014), The immersion mode ice nucleation behavior of mineral dusts: A comparison of different pure and surface modifed dust, Geophys. Res. Lett., 41, doi:10.1002/2014GL061317.
Augustin-Bauditz et al. (2015), The immersion freezing behavior of mineral dust particles mixed with biological substances, Atmos. Chem. Phys. Discuss., 15.
Hartmann et al. (2013), Immersion freezing of ice nucleating active protein complexes, Atmos. Chem. Phys., 13, 5751-5766.
Hartmann et al. (2016), Immersion freezing of kaolinite - scaling with particle surface area, J. Atmos. Sci., 73, 263-278, doi:10.1175/JAS-D-15-0057.1.
Hiranuma et al. (2015), A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of seventeen ice nucleation measurement techniques, Atmos. Chem. Phys., 15, 2489–2518, doi:10.5194/acp-15-2489-2015.
Kupiszewski et al. (2015), The Ice Selective Inlet: a novel technique for exclusive extraction of pristine ice crystals in mixed-phase clouds, Atmos. Meas. Tech., 8, 3087-3106, doi:10.5194/amt-8-3087-2015.
Niedermeier et al. (2014), A computationally efficient description of heterogeneous freezing: A simplified version of the Soccer ball model, Geophys. Res. Lett.,41, doi:10.1002/2013GL058684.
Niedermeier et al. (2015), Can we define an asymptotic value for the ice active surface site density for heterogeneous ice nucleation?, J. Geophys. Res., doi:10.1002/2014JD022814.
Pummer et al. (2015), Ice nucleation by water-soluble macromolecules, Atmos. Chem. Phys., 15, 4077–4091, doi:10.5194/acp-15-4077-2015.
Schenk et al. (2014), Characterization and first results of an ice nucleating particle measurement system based on counterflow virtual impactor technique, Atmos. Meas. Tech., 7, 10585-10617, doi:10.5194/amtd-7-10585-2014.
Schmidt et al. (2015), In-situ single submicron particle composition analysis of ice residuals from mountain-top mixed-phase clouds in Central Europe, Atmos. Chem. Phys. Discuss., 15, 4677-4724, doi:10.5194/acpd-15-4677-2015, doi:10.5194/acpd-15-4677-2015.
Tobo et al. (2012), Impacts of chemical reactivity on ice nucleation of kaolinite particles: A case study of levoglucosan and sulfuric acid, Geophys. Res. Lett., 39 (L19803), doi:10.1029/2012GL053007.
Wex et al. (2014), Kaolinite particles as ice nuclei: learning from the use of different kaolinite samples and different coatings, Atmos. Chem. Phys., 14, doi:10.5194/acp-14-5529-2014.
Wex et al. (2015), Intercomparing different devices for the investigation of ice nucleating particles using Snomax as test substance, Atmos. Chem. Phys., 15, 1463–1485, doi:10.5194/acp-15-1463-2015.
Worringen et al. (2015), Single-particle characterization of ice-nucleating particles and ice particle residuals sampled by three different techniques, Atmos. Chem. Phys., 15, 4161-4178, doi:10.5194/acp-15-4161-2015.