FOR 1525:  INUIT - Ice Nuclei Research Unit

• Subject Area: Geosciences
• Term: from 2011 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 170852269

Ice crystals in the atmosphere play an important role for the formation of precipitation and for the radiative properties of clouds. Mixed-phase clouds are clouds that consist of both, super-cooled liquid droplets and ice particles. They account for a large fraction of the clouds in the atmosphere but our knowledge on the microphysical properties of these clouds is still limited.
An important question is how ice forms in these clouds. While it is well established that an ice nucleus is needed as a seed for the initial formation of an ice crystal in mixed-phase clouds many questions remain to be answered on the concentration and variability of atmospheric ice nuclei and their physico-chemical properties.
The Research Unit studies heterogeneous ice formation in the atmosphere. The studies include laboratory investigations on the nature of the nucleation process and on the chemical, microphysical and biological characterisation of atmospherically relevant ice nuclei (as a function of temperature and water saturation). Intensive field experiments are conducted as well as monitoring surveys to study the number concentration, variability, size, chemical composition, surface properties and sources of atmospheric ice nuclei in different freezing modes. Various state-of-the-art methods and facilities are used for the characterisation of the ice nuclei.
Ice nucleating properties of mineral dust particles, volcanic ash and biological ice nuclei are a focus of attention within the Research Unit. The results of the experimental investigations are fed into a cloud process model and a cloud-resolving mesoscale model to improve the representation of clouds in the models, to simulate cloud processes and to quantify the contribution of ice nuclei types and freezing modes.

• DFG Programme: Research Units

Projects

• Central Coordination and Administration of the INUIT research unit (Applicant Curtius, Joachim )
• Chemical and mineralogical characterization of ice nucleating particles and ice particle residuals (Applicants Bingemer, Heinz ;  Ebert, Martin )
• Composition analysis of ice particle residuals combining aerosol mass spectrometry and counterflow virtual impactor technique (Applicants Schneider, Johannes ;  Stratmann, Frank )
• Comprehensive process studies of heterogeneous ice nucleation: from single cloud droplets to cloud simulations. (Applicant Möhler, Ottmar )
• From lab to field: examining immersion freezing of atmospheric relevant ice nucleating particles (Applicant Wex, Heike )
• Heterogeneous ice nucleation induced by porous materials (Applicant Koop, Thomas )
• In situ measurements of ice nucleating particles (INP) and quantification of biological INP (Applicant Curtius, Joachim )
• Screening and characterization of biological ice nuclei and their influence on the ice nucleation activity of soil and mineral dust. (Applicant Fröhlich, Janine )
• Statistics of Ice Nucleation Conditions in Mixed-Phase Clouds (Applicant Hoose, Corinna )
• The importance of ice nucleating particle types and modes for the initiation of the ice phase and precipitation: Model simulations based on laboratory measurements. (Applicants Diehl, Karoline ;  Szakáll, Miklós )

• Spokesperson: Professor Dr. Joachim Curtius