title: Contact freezing efficiency of mineral dust aerosols studied in an electrodynamic balance: quantitative size and temperature dependence for illite particles.
abstract: Contact freezing has long been discussed as a candidate for cloud ice formation at temperatures warmer than about -25 degrees C, but until now the molecular mechanism underlying this process has remained obscure and little quantitative information about the size and temperature dependent contact freezing properties of the various aerosol species is available. In this contribution, we present the first quantitative measurements of the freezing probability of a supercooled droplet upon a single contact with a size selected illite mineral particle. It is found that this probability is a strong function of temperature and aerosol particle size. For the particles investigated and on the minute time scale of the experiment, contact freezing indeed dominates immersion freezing for all temperatures.
authors.affiliation: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, P.O. Box 3640, Karlsruhe, Germany. Nadine.Hoffmann@kit.edu
authors.forename: Nadine
authors.initials: N
authors.lastname: Hoffmann
authors.affiliation: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, P.O. Box 3640, Karlsruhe, Germany.
authors.forename: Denis
authors.initials: D
authors.lastname: Duft
authors.affiliation: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, P.O. Box 3640, Karlsruhe, Germany.
authors.forename: Alexei
authors.initials: A
authors.lastname: Kiselev
authors.affiliation: Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, P.O. Box 3640, Karlsruhe, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Leisner