ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-3-1439-2003 Comment on evidence for surface-initiated homogeneous nucleation Kay J. E. 1 Tsemekhman V. 2 Larson B. 1 Baker M. 1 Swanson B. 1 Department of Earth and Space Sciences, University of Washington, Seattle, USA Applied Physics Laboratory, University of Washington, Seattle, USA 22 09 2003 3 5 1439 1443 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/3/1439/2003/acp-3-1439-2003.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/3/1439/2003/acp-3-1439-2003.pdf

We investigate theoretical, laboratory, and atmospheric evidence for a recently proposed hypothesis: homogeneous ice nucleation initiates at the surface, not in the volume, of supercooled water drops. Using existing thermodynamic arguments, laboratory experiments, and atmospheric data, we conclude that ice embryo formation at the surface cannot be confirmed or disregarded. Ice nucleation rates measured as a function of drop size in an air ambient could help distinguish between volume and surface nucleation rates.