Regensburg 2016 – scientific programme

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UP: Fachverband Umweltphysik

UP 16: Atmosphere - Laboratory Studies

UP 16.2: Talk

Thursday, March 10, 2016, 16:15–16:30, H41

Heterogeneous nucleation of ice on mineral surfaces: the effect of crystal microstructure — •Alexei Kiselev and Thomas Leisner — Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

Mineral dust have been shown to be the most abundant ice-nucleating particle (INP) type in the Earth's atmosphere. However, the ice nucleating efficacy of mineral dust ranges over orders of magnitude and the question, what property (or combination of properties) is responsible for any particular mineral dust aerosol being bad or good INP, is still under debate. In the recent experiments on the deposition growth of ice on feldspar conducted in an Environmental Scanning Electron Microscope (ESEM), we have noticed that ice crystals preferentially nucleate at sites where ideal crystalline structure of feldspar is distorted due to the twinning or exsolution of different feldspar types: K-rich microcline and Na/Ca-rich albite. At the same time the crystal lattice distortion does not destroy the orientation alignment of ice crystals caused by epitaxial growth of ice with its (110) plane on top of the (010) surface of feldspar. Using the 3D structural models of the crystalline lattices of feldspar and ice, we suggest an interpretation of the observational data and discuss the possible implication of this phenomena for the atmospheric ice nucleation research.