Heterogeneous Ice Nucleation of Dusts: Overview of Results from the INUIT Project (Invited Presentation)

The heterogeneous nucleation of ice on various types of dusts including agricultural soil dusts as well mineral dusts from deserts and semi-arid areas is studied within the German coordinated research project INUIT (Ice Nuclei Research Unit). The studies include laboratory investigations and chamber studies on the nature of the ice nucleation processes and on the chemical, microphysical, surface and mineralogical characterization of the ice nucleating particles as a function of temperature and water saturation. Specific sample substances such as feldspar, porous materials, ash and cellulose are studied in detail as well as soil dust samples from different regions. The influence of organic or biologic components associated with soil dusts on the ice nucleating properties is studied. Intensive field experiments were conducted in Cyprus (March/April 2016) and at the High Altitude Research Station Jungfraujoch (Jan/Feb 2017), to study the number concentration, variability, chemical composition, sources and vertical distribution of atmospheric ice nuclei, including dust transported from Northern Africa. Modelling activities focus on the numerical assessment of heterogeneous ice nucleation and its importance for cloud parameters integrating the results of the laboratory and field observations with cloud-scale and larger scale modelling. An overview of recent key results is given.