Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 4 7 2004 10.5194/acp-4-1997-2004 http://www.atmos-chem-phys.net/4/1997/2004/ http://www.atmos-chem-phys.net/4/1997/2004/acp-4-1997-2004.html http://www.atmos-chem-phys.net/4/1997/2004/acp-4-1997-2004.pdf 1997 2000 2004-10-04 Laboratory evidence for volume-dominated nucleation of ice in supercooled water microdroplets D. Duft T. Leisner Institut für Physik, Technische Universität Ilmenau, 98684 Ilmenau, Germany We report on measurements of the rate of homogeneous ice nucleation in supercooled water microdroplets levitated in an electrodynamic balance. By comparison of the freezing probability for droplets of radius 49µm and 19µm, we are able to conclude that homogeneous freezing is a volume-proportional process and that surface nucleation might only be important, if at all, for much smaller droplets.